Treadmill with automatic speed control and control module of the same

ABSTRACT

A treadmill includes a body having a belt for supporting an exerciser, an exerciser detecting portion installed in a predetermined area of the body to detect movement of the exerciser, a driving motor coupled to the body to drive the belt, a control portion for generating a first control signal for adjusting a rotation speed of the driving motor based on a signal received from the exerciser detecting portion, a motor driving portion for adjusting the rotation speed of the driving motor according to the first control signal received from the control portion, and an electrical braking portion for reducing the rotation speed of the driving motor. The treadmill quickly follows acceleration or deceleration of an exerciser; provides an experience as if the exerciser is exercising on the ground, thereby improve an exerciser&#39;s exercising experience; accepts various exercising patterns of an exerciser; resolves a problem in that a motor driving portion is tripped due to a load caused by quick deceleration; and preprocesses measured values of an exerciser&#39;s position to resolve a problem in that a speed of a belt cannot be controlled due to measurement errors contained in measured values.

CLAIM FOR PRIORITY

This application claims priority to Korean Patent Application No.10-2007-0104222 filed on Oct. 16, 2007, Korean Patent Application No.10-2007-0129436 filed on Dec. 12, 2007, Korean Patent Application No.10-2007-0129438 filed on Dec. 12, 2007, Korean Patent Application No.10-2007-0129439 filed on Dec. 12, 2007, Korean Patent Application No.10-0136452 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136453 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136455 filed on Dec. 24, 2007, Korean Patent Application No,10-2007-0136456 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136457 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136458 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136459 filed on Dec. 24, 2007, Korean Patent Application No.10-2007-0136460 filed on Dec. 24, 2007, and Korean Patent ApplicationNo. 10-2007-0136462 filed on Dec. 24, 2007 in the Korean IntellectualProperty Office (KIPO), the entire contents of which are herebyincorporated by reference.

BACKGROUND

1. Technical Field

The present invention relates to a treadmill, and more particularly, toa treadmill with an automatic speed control function in which a speed ofa rotating belt is automatically controlled according to an exercisingspeed and an exercising state of an exerciser.

2. Description of the Related Art

In a conventional treadmill, in order to control a speed of a rotatingbelt, an exerciser has to manipulate a speed control button whilewalking or running and has to passively follow the manually controlledspeed of the rotating belt. Therefore, such a conventional treadmilldoes not provide a good exercising experience to an exerciser and isalso difficult to realize a natural feeling that an exerciser can havewhile walking or running on the ground.

In order to overcome the above problems, techniques for measuring aposition of an exerciser to automatically control a speed of a rotatingbelt have been developed. For example, Korean Patent No. 10-0398330discloses a treadmill which measures a position of an exerciser using anultrasonic sensor arranged below a control panel to locate an exerciserin a central region of the treadmill belt. The treadmill accelerates therotating belt speed to move the exerciser back to the central region ifthe exerciser is ahead of the central region, and the treadmilldecelerates the belt speed to return an exercise to the central regionif the exerciser is behind the central region.

The treadmill disclosed in Korean Patent No. 10-0398330 performsacceleration or deceleration when a position of the exerciser is withina certain range from the central region, but the treadmill cannot handlevarious situations such as quick deceleration when an exerciser desiresto abruptly stop while running at a high speed.

In addition, when a quick deceleration occurs, an overload occurs in amotor driving portion, and the motor driving portion stops driving themotor to protect itself. Thus, a conventional treadmill cannot execute aquick deceleration.

Also, a conventional treadmill performs a deceleration at a fixed slowspeed, independently of a driving speed, within a range of adeceleration which does not exceed an allowable range of a motor drivingportion, and performs an emergency stop operation of the motor drivingportion using a natural friction force which works on a belt and adriving motor.

Also, since an abrupt deceleration during exercise can cause anexerciser to fall due to inertia and potential injury risks, aconventional treadmill has implemented a slow deceleration or adeceleration using a natural friction force.

For the foregoing reasons, an exerciser who exercises on a conventionaltreadmill has a different feeling from what he/she has while walking orrunning on the actual ground. Further, such a conventional treadmillcannot effectively implement various exercising patterns of anexerciser.

In order to improve an overall exercise experience and to cope withvarious exercising patterns of an exerciser, a treadmill needs torapidly follow acceleration and deceleration of an exerciser, but aconventional treadmill cannot perform quick deceleration and thus cannotprovide a satisfactory automatic speed control function.

In the treadmill disclosed in Korean Patent No. 10-0398330 whichmeasures a position of an exerciser by an ultrasonic sensor in order tocontrol a speed of a belt to locate an exerciser in a central region, ameasured value of an exerciser's position received from an ultrasonicsensor may contain erroneous values. Therefore, it is difficult toimplement an automatic speed control function using only a technique formeasuring an exerciser's position by an ultrasonic sensor in atreadmill.

In addition, measured values received from an ultrasonic sensor can bedistorted due to various ambient noise, and undesired measured values,for example, a position value of an arm or a leg, may be obtained whilean exerciser walks or runs. Such signal distortion and undesiredmeasured values make it difficult for a treadmill to automaticallycontrol a speed of a belt.

Korean Patent Publication Nos. 10-2007-0015687, 10-2007-0081476,10-2007-0082277, and 10-2007-0082929 disclose techniques and mechanismsin which load sensors are arranged below front and rear portions of abelt, measured values obtained by load sensors are used to calculate anexerciser's position, and a speed of a rotating belt is controlled basedon a difference between a calculated exerciser's position and areference position.

However, the above-described techniques using load sensors have aproblem in that a cycle of a load that is applied to a load sensordepends on a speed of an exerciser, and a cycle of a load of when anexerciser runs at a highest speed is 2 or 3 times per second. This makesit very difficult to smoothly control the belt speed.

Also, a position of an exerciser's foot continuously varies due to amovement of the belt even at a moment that an exerciser's foot pushesthe belt, and the frequency with which the exerciser's feet make contactwith the belt when an exerciser walks on the belt is not equal to thatwhen an exerciser runs on the belt. Thus, it is difficult to accuratelycalculate a position of an upper body of an exerciser or the center ofgravity.

In addition, the above-mentioned Korean Patent Publications have notmentioned a control method for coping with various exercising patternsof an exerciser, such as quick acceleration or quick deceleration, andso it is difficult to automatically control the belt speed only using adifference between an exerciser's position and a reference position in amanner that provides satisfactory automatic speed control.

SUMMARY

It is an object of the present invention to resolve a problem in that,in a conventional treadmill, an exercising experience is unsatisfactorysince an exerciser passively exercises on a treadmill and the feeling ofexercising on the ground is not realized.

It is another object of the present invention to resolve a problem inthat a conventional treadmill does not quickly follow acceleration anddeceleration of an exerciser.

It is still another object of the present invention to resolve a problemin that a conventional treadmill does not accept various exercisingpatterns of an exerciser.

It is yet still another object of the present invention to resolve aproblem in that, in a conventional treadmill, a motor driving portiondoes not endure an overload caused by quick deceleration.

It is yet still another object of the present invention to resolve aproblem in that a conventional treadmill cannot control a speed of abelt due to measurement errors contained in measured values of anexerciser's position.

In order to achieve the above objects, one aspect of the presentinvention provides a treadmill, comprising: a body having a belt forsupporting an exerciser; an exerciser detecting portion installed in apredetermined area of the body to detect movement of the exerciser; adriving motor coupled to the body to drive the belt; a control portionfor generating a first control signal for adjusting a rotation speed ofthe driving motor based on a signal received from the exerciserdetecting portion; a motor driving portion for adjusting the rotationspeed of the driving motor according to the first control signalreceived from the control portion; and an electrical braking portion forreducing the rotation speed of the driving motor.

Preferably, in the treadmill, in order to reduce the rotation speed ofthe driving motor, the motor driving portion generates a first brakingtorque, and the electrical braking portion generates a second brakingtorque.

Preferably, in the treadmill, the electrical braking portion generatesthe second braking torque when a provision braking torque by the firstcontrol signal is equal to or greater than the first braking torque.

Preferably, in the treadmill, the second braking torque is equal to orgreater than a difference between the provision braking torque and thefirst braking torque.

Preferably, in the treadmill, the electrical braking torque comprises aswitching portion which operates to generate the second braking torquewhen the provision braking torque is equal to or greater than the firstbraking torque.

Preferably, in the treadmill, the electrical braking torque comprises aswitching portion which operates when a voltage of regenerative energyflowing into the motor driving portion from the driving motor is equalto or more than a predetermined reference in case of decreasing therotation speed of the driving motor.

Preferably, in the treadmill, the switching portion operates by a secondcontrol signal transmitted from the control portion.

Preferably, in the treadmill, the electrical braking portion comprises aswitching portion which operates when a voltage applied between bothoutput terminals of a converting portion of the motor driving portion isequal to or more than a predetermined reference.

Preferably, in the treadmill, the electrical braking torque comprises abraking resistor which converts regenerative energy flowing into themotor driving portion from the driving motor into heat in case ofdecreasing the rotation speed of the driving motor.

Preferably, in the treadmill, both ends of the braking resistor areelectrically connected to both output terminals of the convertingportion of the motor driving portion, respectively.

Preferably, in the treadmill, one end of the braking resistor iselectrically connected to one end of a switching portion which operateswhen a voltage of the regenerative energy is equal to or more than apredetermined reference.

Preferably, in the treadmill, the electrical braking torque transfers atleast a part of regenerative energy flowing into the motor drivingportion from the driving motor to a power supplying portion forsupplying electrical power to the motor driving portion in case ofdecreasing the rotation speed of the driving motor.

Preferably, in the treadmill, the electrical braking portion comprises aswitching portion which operates when a voltage of the regenerativeenergy is equal to or more than a predetermined reference.

Preferably, in the treadmill, the control portion comprises apre-processing portion for generating a converted value used to generatethe first control signal by using a measured value corresponding to thesignal transmitted from the exerciser detecting portion.

Preferably, in the treadmill, the pre-processing portion generates theconverted value by comparing the measured value to a past value of an atleast first most recent or earlier previous unit time from a currentunit time.

Preferably, in the treadmill, the control portion comprises a referenceposition generating portion for generating a reference position valuewhich represents a reference position from the exerciser detectingportion for acceleration and deceleration of the driving motor.

Preferably, in the treadmill, the control portion comprises a drivingcommand portion which receives the reference position value from thereference position generating portion, generates the first controlsignal and transmits the first control signal to the motor drivingportion.

Preferably, in the treadmill, the reference position generating portionvaries the reference position value by a predetermined criterion.

Preferably, in the treadmill, the reference position generating portionvaries the reference position value corresponding to a speed of thebelt.

Preferably, in the treadmill, the reference position generating portionadjusts the reference position value to be short from the exerciserdetecting portion if the speed of the belt is fast, and adjusts thereference position value to be far from the exerciser detecting portionif the speed of the belt is slow.

Preferably, in the treadmill, the reference position generating portiondecreases the reference position value if the speed of the belt is fastand increases the reference position value if the speed of the belt isslow.

In order to achieve the above objects, another aspect of the presentinvention provides a treadmill, comprising: a body having a belt forsupporting an exerciser; an exerciser detecting portion which detectsmovement of the exerciser and is installed in a predetermined area ofthe body at the height of equal to or more than 50 cm and equal to orless than 150 cm from a top surface of the belt; a driving motor coupledto the body to drive the belt; a control portion for generating acontrol signal for adjusting a rotation speed of the driving motor basedon a signal received from the exerciser detecting portion; and a motordriving portion for adjusting the rotation speed of the driving motoraccording to the control signal received from the control portion.

Preferably, in the treadmill, the exerciser detecting portion isinstalled at the height of equal to or less than 70 cm and equal to orless than 110 cm from the top surface of the belt.

Preferably, in the treadmill, the control portion comprises apre-processing portion for generating a converted value used to generatethe control signal by using a measured value corresponding to the signaltransmitted from the exerciser detecting portion.

Preferably, in the treadmill, the exerciser detecting portion comprisesan ultrasonic sensor which has a measuring cycle of equal to or morethan 4 Hz and equal to or less than 100 Hz.

Preferably, in the treadmill, a radiation angle of the ultrasonic sensoris within about 25°.

Preferably, the treadmill further comprises an electrical brakingportion for decreasing a rotation speed of the driving motor.

Preferably, the treadmill further comprises a regenerative energyprocessing portion for processing regenerative energy flowing into themotor driving portion from the driving motor when the driving motor isbraked.

Preferably, in the treadmill, the reference position generating portionvaries the reference position value based on a predetermined criterion.

One aspect of the present invention provides a control module for atreadmill, comprising: a base substrate with an electrical wire lineformed therein; a control portion coupled to the base substrate andhaving a semiconductor circuit electrically connected to the electricalwire line; and a connecting terminal coupled to the base substrate andelectrically connected to a motor driving portion for driving a drivingmotor and an exerciser detecting portion for measuring a position of anexerciser, wherein the control portion adjusts a rotation speed of thedriving motor based on a signal transmitted from the exerciser detectingportion and transmits a first control signal to the motor drivingportion to provide an electrical braking torque to the driving motor inorder to decelerate the driving motor.

Preferably, in the control module for the treadmill, the control portioncomprises a pre-processing portion for generating a converted value usedto generate the first control signal by using a measured valuecorresponding to the signal transmitted from the exerciser detectingportion.

Preferably, in the control module for the treadmill, the pre-processingportion comprises a data converting portion which compares a currentmeasured value to a past value of an at least first most recent orearlier previous unit time from a current unit time to generate theconverted value.

Preferably, in the control module for the treadmill, the control portioncomprises a reference position generating portion for generating areference position value which represents a reference position from theexerciser detecting portion for acceleration and deceleration of thedriving motor.

Preferably, in the control module for the treadmill, the control portioncomprises a driving command portion which receives the referenceposition value from the reference position generating portion, generatesthe first control signal and transmits the first control signal to themotor driving portion.

Preferably, in the control module for the treadmill, the referenceposition generating portion varies the reference position value by apredetermined criterion.

Preferably, in the control module for the treadmill, the referenceposition generating portion varies the reference position valuecorresponding to a rotation speed of the driving motor.

Preferably, in the control module for the treadmill, the referenceposition generating portion adjusts the reference position value to beshort from the exerciser detecting portion if the rotation speed of thedriving motor is fast, and adjusts the reference position value to befar from the exerciser detecting portion if the rotation speed of thedriving motor is slow.

Preferably, in the control module for the treadmill, the referenceposition generating portion decreases the reference position value ifthe rotation speed of the driving motor is fast and increases thereference position value if the rotation speed of the driving motor isslow.

Preferably, the control module for the treadmill further comprises anelectrical braking portion which is electrically connected to the motordriving portion and provides the electrical braking torque.

Preferably, in the control module for the treadmill, the electricalbraking torque comprises a resistor, and the control module furtherincludes a heat sink portion which is made of a metal to discharge heatgenerated in the resistor.

Preferably, in the control module for the treadmill, in order todecrease the rotation speed of the driving motor, the motor drivingportion generates a first braking torque, and the electrical brakingportion generates a second braking torque.

Preferably, in the control module for the treadmill, the electricalbraking portion generates the second braking torque when the electricalbraking torque is equal to or greater than the first braking torque.

Preferably, in the control module for the treadmill, the second brakingtorque is equal to or greater than a difference between the electricalbraking torque and the first braking torque.

Preferably, in the control module for the treadmill, the electricalbraking torque comprises a switching portion which operates when theelectrical braking torque is equal to or greater than the first brakingtorque.

Preferably, in the control module for the treadmill, the switchingportion operates by a second control signal transmitted from the controlportion via an electrical braking portion connecting terminal whichelectrically connects the control portion and the electrical brakingportion among the connecting terminals.

A treadmill according to the present invention quickly followsacceleration or deceleration of an exerciser and thus has an advantageof realizing a feeling like what an exerciser has while exercising onthe ground to thereby improve an exerciser's exercising feeling.

The treadmill according to the present invention has an advantage ofaccepting various exercising patterns of an exerciser.

The treadmill according to the present invention has an advantage ofresolving a problem in that a motor driving portion is tripped due to aload caused by quick deceleration.

The treadmill according to the present invention adjusts a location of asensor for measuring an exerciser's position and thus has an advantageof minimizing noise and measurement errors contained in measuredsignals.

The treadmill according to the present invention pre-processes measuredvalues of an exerciser's position and thus has an advantage of resolvinga problem in that a speed of a belt can not be controlled due tomeasurement errors contained in measured values.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the present invention will become more apparentby describing in detail example embodiments of the present inventionwith reference to the accompanying drawings, in which:

FIG. 1 is a measurement graph illustrating various load patterns of atreadmill according to the exemplary embodiment of the presentinvention;

FIG. 2 is a side view illustrating the treadmill according to anexemplary embodiment of the present invention;

FIG. 3 is a block diagram illustrating the treadmill according to anexemplary embodiment of the present invention;

FIGS. 4 to 6 are various circuit diagrams illustrating an electricalbraking method using an AC motor according to an exemplary embodiment ofthe present invention;

FIGS. 7 to 9 are various circuit diagrams illustrating electricalbraking methods using a DC motor according to an exemplary embodiment ofthe present invention;

FIGS. 10 to 12 are block diagrams illustrating a control portionaccording to an exemplary embodiment of the present invention.

FIG. 13 is a flowchart illustrating a control method of the controlportion according to an exemplary embodiment of the present invention;

FIG. 14 is a flowchart illustrating an operation of a state determiningportion according to an exemplary embodiment of the present invention;

FIGS. 15 and 16 are flowcharts illustrating an operation of a dataconverting portion according to an exemplary embodiments of the presentinvention;

FIG. 17 is a flowchart illustrating an operation of a reference positiongenerating portion according to an exemplary embodiment of the presentinvention;

FIG. 18 is a graph illustrating a method for restricting a maximumacceleration/deceleration according to an exemplary embodiment of thepresent invention;

FIGS. 19 and 20 are flowcharts illustrating a sensitivity adjustingmethod performed by a sensitivity adjusting portion according to anexemplary embodiments of the present invention; and

FIG. 21 is a perspective view illustrating a control module for thetreadmill with the automatic speed control function according to anexemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. However,it should be understood that there is no intent to limit the inventionto the particular forms disclosed, but on the contrary, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention. In the drawings, like referencenumerals denote like parts.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these teens. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present invention. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected or “coupled” to another element, it can be directly connectedor coupled to the other element or intervening elements may be present.In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”,“comprising”, “includes” and/or “including”, when used herein, specifythe presence of stated features, integers, steps, operations, elements,components or a combination thereof these, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Hereinafter, a current value X_(r) ^(T) represents a current measuredvalue X_(r) or a current converted value X_(r)′, and is a representativeterm for describing current data in a stream of time. That is, a currentvalue X_(r) ^(T) means data corresponding to a current time (e.g.,current measuring cycle).

Similarly, a past value X_(r−i) ^(T) (i=1, . . . n) represents a pastmeasured value (i=1, . . . n) or a past converted value X_(r−i)′ (i=1, .. . n), and is a representative term for describing past data in astream of time. That is, a past value X_(r−i) ^(T) (i=1, . . . n) meansdata corresponding to a past time (e.g., past measuring cycle).

Also, a data value X_(r−i) ^(o) (i=0, . . . , n) is a representativeterm for describing data containing a current value X_(r) ^(T) and apast value X_(r−i) ^(T) (i=1, . . . n).

Also, a belt speed, a driving belt speed, a rotation speed of a drivingmotor, and a driving speed have the same meaning, and so even though oneterm is described as an example, it may contain the meaning of otherterms.

That is, a belt speed or a driving belt speed can be calculated byoperating a rotation speed of a driving motor and a constant like aradius of a roller, can be calculated by using/operating a signalprovided to a driving motor from a motor driving portion, or can becalculated by using a control signal (i.e., a first control signal)provided to a motor driving portion from a control portion.

A belt speed, a driving belt speed, a rotation speed of a driving motormay be directly measured by using a predetermined measuring means.

An exemplary embodiment of the present invention is described below indetail with reference to attached drawings.

FIG. 1 is a measurement graph illustrating various load patterns of atreadmill that can be used according to an exemplary embodiment of thepresent invention. The graph of FIG. 1 comparatively shows maximumallowable decelerations 110 and 120 of a motor driving portion that canbe generated, due to a trip occurring in a motor driving portion, whenbraking a driving motor according to a driving speed of a belt if anelectrical braking portion of the present invention is not provided. Thegraph of FIG. 1 also shows the target decelerations 210 and 220 used toprovide an exerciser with an exercising feeling like what an exerciserhas while exercising on an actual ground.

In additional, FIG. 1 shows problems which occur when a fixed smalldeceleration 310 and a fixed high deceleration 320 are providedaccording to a conventional art in a state that does not variablycontrol a deceleration depending on a driving speed of a belt.

Since an experiment for performing quick deceleration while an exerciserexercises on a treadmill at a high speed is very risky, data in thegraph of FIG. 1 are ones measured without an exerciser on the treadmill.The maximum allowable deceleration 110 is measured by using a motordriving portion with a capacity of 2.2 kW, and the maximum allowabledeceleration 120 is measured by using a motor driving portion with acapacity of 3.7 kW.

The graph of FIG. 1 is first described below centering on the maximumallowable deceleration 110 measured using a motor driving portion with acapacity of 2.2 kW.

The maximum allowable deceleration 110 represents a maximum allowableload of a motor driving portion to brake a belt in a treadmill whichdoes not have an electrical braking portion of the present invention.Areas A-a, A-b and A-c below a maximum allowable deceleration 110 linesegment are deceleration areas containing an allowable load of a motordriving portion, and a deceleration in these areas can be performed onlyby a braking torque (first braking torque) of a motor driving portionitself without using the electrical braking portion of the presentinvention.

Areas B-a, B-b and B-c above the maximum allowable deceleration 110 linesegment are deceleration areas which exceed an allowable load of a motordriving portion, and a deceleration in these areas needs a brakingtorque (second braking torque) provided by the electrical brakingportion of the present invention.

As can be seen in the graph of FIG. 1, a maximum allowable decelerationdepends on a driving speed of a belt.

In a low speed section in which a driving speed of a belt is 5 km/h, amaximum allowable deceleration is about 7.9 km/h per second, but in ahigh speed section in which a driving speed of a belt is 19 km/h, amaximum allowable deceleration is about 2.3 km/h per second.

Since a kinetic energy is larger as a driving speed of a belt is faster,a motor driving portion requires a larger load for braking, and so amaximum allowable deceleration at which a trip occurs in a motor drivingportion becomes smaller. That is, if the electrical braking portion ofthe present invention is not provided, a larger deceleration isimpossible as a driving speed of a belt is faster, and so it can be seenthat there is a problem in that a belt which rotates at a speed of, forexample, 19 km/h cannot perform a deceleration of more than 2.3 km/h persecond.

In the present invention, it has been determined that an exerciser has atendency to stop within a predetermined time regardless of a drivingspeed of a belt when an exerciser desires to stop while walking orrunning on a treadmill. Through an experiment for a relationship betweena belt speed and a stop time using a plurality of subjects, it wasdetermined that most exercisers feel satisfied when a stop time is in arange of 1.5 seconds to 5 seconds, preferably 2 seconds to 4 seconds.

It was also found through an experiment that a deceleration of aninitial decelerating stage corresponds to a stop time which is a timetaken for a belt which rotates at a certain speed to completely stop,and a deceleration tendency of an exerciser described above can besatisfied even when a stop time is varied during a deceleration.

Hereinafter, a stop time means the time taken for a belt to stopaccording to a deceleration of an exerciser.

A ratio between a belt driving speed and a stop time corresponds to anexerciser's desired deceleration, and so, in the graph of FIG. 1, targetdecelerations 210 and 220 with respect to a belt driving speed arerespectively indicated by an upper target deceleration 220 correspondingto a stop time of 2 seconds and a lower target deceleration 210corresponding to a stop time of 4 seconds.

Therefore, it is preferable that areas A-b and B-b between the lower andupper target deceleration 210 and 220 are set as target decelerationareas where a deceleration of a belt is controlled. In the exemplaryembodiment of the present invention, a target deceleration is set to 3seconds.

As can be seen in FIG. 1, the target decelerations 210 and 220 areincreases as a belt driving speed increases, but in a conventionaltreadmill having no electrical braking portion as in the presentinvention, there is a problem in that the maximum allowabledecelerations 110 and 220 decreases as a belt driving speed increases.

That is, it is necessary to use braking areas B-a, B-b and B-c where abraking torque (second braking torque) of the electrical braking portionis additionally provided since it is impossible to brake only by using abraking torque (first braking torque) of a motor driving portion itself.A relationship with the target decelerations 210 and 220 is described inmore detail below.

Areas A-a and B-a defined by the upper target deceleration 220 are areaswhich may pose a risk to an exerciser due to a very fast deceleration,and, in these areas, there is a need for restricting a maximumdeceleration.

Areas A-b and B-b defined by the upper target deceleration 220 and thelower target deceleration 210 are areas which provide a fastdeceleration while not risking an exerciser. Particularly, the left areaA-b defined by the maximum allowable deceleration 110 is an area inwhich a braking torque (first braking torque) of a motor driving portionis provided, and the right area B-b defined by the maximum deceleration110 is an area which needs a braking torque (second braking torque) ofan electrical braking portion.

Areas A-c and B-c defined by the lower target deceleration 210 are areaswhich provide a slower deceleration than the areas A-b and B-b but needa provision of a braking torque. Particularly, the left area A-c definedby the maximum allowable deceleration 110 is an area in which a brakingtorque (first braking torque) of a motor driving portion is provided,and the right area B-c defined by the maximum allowable deceleration 110is an area which needs a braking torque (second braking torque) of theelectrical braking portion.

Therefore, as can be seen in FIG. 1, an exerciser who requires the uppertarget deceleration 220 needs a braking torque (second braking torque)of the electrical braking portion at a belt speed of more than about 8km/h, and an exerciser who requires the lower target deceleration 210needs a braking torque (second braking torque) of the electrical brakingportion at a belt speed of more than about 11.5 km/h.

An exerciser usually exercises on a treadmill at a speed of 7 km/h to 15km/h, and there are exercisers who exercise on a treadmill even at aspeed of more than 20 km/h.

A treadmill with only a braking torque (first braking torque) providedby a motor driving portion cannot realize a braking of a decelerationdesired by an exerciser even in a general exercising speed range. Such aproblem is resolved by providing the electrical braking portion of thepresent invention.

A conventional treadmill provides a fixed slow deceleration 310 at adriving speed of the whole section and so cannot provides a decelerationdesired by an exerciser.

If a motor driving portion with a large capacitor of 3.7 kW is employed,then the maximum allowable deceleration 120 is increased compared to amotor driving portion with a capacity of 2.2 kW, but its increment rateis large in a low speed section and is small in a high speed section.

The maximum allowable deceleration 120 is increased with an oppositetendency to the target decelerations 210 and 220.

That is, the target deceleration requires a large deceleration at a highspeed rather than a low speed, but even though a motor driving portionwith a large capacity is employed, an incremented rate of a decelerationat a low speed is large, and an incremented rate of a deceleration at ahigh speed is small. Therefore, there is a problem in that it isimpossible to provide a braking torque corresponding to a targetdeceleration. For such reasons, it is preferable to provide a brakingtorque (second braking torque) through the electrical braking portion ofthe present invention.

Also, if a fixed high speed deceleration 320 is provided at a drivingspeed of the whole section in order to overcome the above problem of aconventional treadmill, a large to deceleration with which an exerciseris difficult to cope is generated in a low speed section, whereby thereis a problem in that such a deceleration is contained in the areas A-aand B-b which can cause potential risks to an exerciser.

For the foregoing reasons, in the exemplary embodiment of the presentinvention, a deceleration is preferably variably controlledcorresponding to a driving speed of a belt.

By using a variable deceleration control method according to the presentinvention, the treadmill of the present invention variably controls adeceleration corresponding to a driving speed of a belt within the lowerareas A-b and A-c defined by the target decelerations 210 and 220 andthe maximum allowable decelerations 110 and 120, without using anelectrical braking portion of the present invention, therebysignificantly improving an exercising feeling compared to theconventional treadmill.

Such a variable deceleration control is provided within a range of thetarget deceleration and is performed by a deceleration control methodwhich will be described with reference to FIGS. 10 to 20.

That is, a target deceleration means a deceleration which is on a targetto improve an exerciser's exercising feeling corresponding to a rotationspeed of a driving motor or a speed of a belt corresponding thereto, anda provision deceleration means a deceleration provided by a treadmill inconsideration of various factors such as a position change rate of anexerciser within a range of the target deceleration. The provisiondeceleration corresponds to a first control signal provided to a motordriving portion 6000 from a control portion 7000.

Here, the target deceleration corresponds to a target braking torque,the provision deceleration corresponds to a provision braking torque,and the maximum allowable deceleration corresponds a braking torque(first braking torque) provided by the motor driving portion 6000.

Therefore, a braking torque (second braking torque) provided by theelectrical braking portion 8000 of the present invention is generatedsuch that a switching portion contained in to the electrical brakingportion 8000, which will be described later, operates when the provisionbraking torque is equal to or more than the first braking torque.

FIG. 2 is a side view illustrating the treadmill according to theexemplary embodiment of the present invention, and FIG. 3 is a blockdiagram illustrating the treadmill according to the exemplary embodimentof the present invention. The treadmill of the present inventioncomprises a body portion 2100, an exerciser detecting portion 3000, adriving motor 4000, a belt 5000, a motor driving portion 6000, and acontrol portion 7000.

The belt 5000 on which the exerciser 1000 walks or runs, the drivingmotor 4000 for driving the belt 5000, the motor driving portion 6000 fordriving the driving motor, and the control portion 7000 are installed inthe body portion 2100. The body portion 2100 can be variously configureddepending on a design of a frame 2110.

The frame 2110 is arranged on one side of the body portion 2100, and acontrol panel 2200 which has an operating portion 2210 with buttonsmanipulated by the exerciser 1000 and a display device 2220 fordisplaying various information, and the exerciser detecting portion 3000for detecting a position of the exerciser 1000 are arranged on one sideof the frame 2110.

The belt 5000 is endlessly rotated by a pair of rollers 2310 and 2320installed in the body portion 2100 and substantially supports theexerciser 1000. One roller 2310 of a pair of rollers 2310 and 2320 isengaged with the driving motor 4000 to receive torque from the drivingmotor 4000.

A torque transferring means 2400 arranged between the driving motor 4000and the roller 2310 may be realized by a gear or a belt. Preferably, thetorque transferring means 2400 is realized by a belt which hasrelatively small noise.

The exerciser detecting portion 3000 comprises a non-contact type sensorsuch as an optical sensor or an ultrasonic sensor and serves andmeasures a distance between the exerciser detecting portion 3000 and theexerciser 1000.

In the exemplary embodiment of the present invention, an ultrasonicsensor is used as the exerciser detecting portion 3000 since an opticalsensor has a problem in that light emitted from an optical sensor may beabsorbed by clothes of the exerciser 1000.

Such a non-contact type sensor measures a distance between the exerciserdetecting portion 3000 and the exerciser 1000 by transmitting a signalat a predetermined interval and receiving a signal reflected from theexerciser 1000. For example, an ultrasonic sensor measures a distancebetween the exerciser detecting portion 3000 and the exerciser 1000 bycalculating half of a reciprocating distance which is obtained bymultiplying a speed at which a signal moves in the air and a time takenfor a signal to return.

In case of an ultrasonic sensor, if a radiation angle (θ) is small, anoise is small, and so a measurement error which may occur when theexerciser 1000 shakes an arm or a leg is reduced, but its price is high.To the contrary, if a radiation angle (θ) is large, its price is low,but noise and a measurement error of the inexpensive sensor areincreased.

In order to overcome the above problem, an ultrasonic sensor with aradiation angle (θ) of equal to or less than about 25° is preferablyused. In the exemplary embodiment of the present invention, a relativelycheap ultrasonic sensor with a radiation angle (θ) of about 25° is used,and a noise and a measurement error resulting from a cheap sensor arecompensated by a control method programmed in the control portion 7000which will be described later.

The exerciser detecting portion 3000 is arranged on one side of the bodyportion 2100 at a height of 50 cm to 150 cm from a top surface of thebelt 5000 in consideration of an adult average height and a detectingarea. Preferably, the exerciser detecting portion 1000 is arranged at aheight of 70 cm to 110 cm from a top surface of the endless belt 5000 inconsideration of a height of a lower pelvis of when the exerciser liftsa leg and a height of an elbow of when the exerciser 1000 swings an armin order to measure a position of an abdomen of the exerciser 1000.

In the exemplary embodiment of the present invention, a position of theexerciser 1000 is measured at a predetermined measuring cycle (forexample, more than 10 Hz) by using an ultrasonic sensor as the exerciserdetecting portion 3000. Since the exerciser 1000 swings an arm at acycle of about 2 Hz to 3 Hz if he/she exercises at a fast speed, aposition of an arm or knee of the exerciser 1000 other than an upperbody of the exerciser 1000 may be contained in a measured value. Inorder to minimize this measurement error, an installation height of theexerciser detecting portion 3000 is adjusted, and the measured value iscompensated by the control portion 7000.

Preferably, a measuring cycle of an ultrasonic sensor is greater than orequal to 4 Hz which is twice the variation cycle of a measured signal(for example, a position variation cycle of an upper body of theexerciser when the exerciser exercises) and less than or equal to 10 Hzin consideration of the maximum distance between the exerciser detectingportion 3000 and the exerciser 1000 which is about 1.5 m and a movingspeed of a sonic wave. More preferably, a measuring cycle of anultrasonic sensor is equal to or more than 6 Hz which is three times ofa variation cycle of a measured signal.

When the exerciser 1000 rapidly runs to accelerate from a current speed,a current position X_(r) of the exerciser 1000 is ahead of a referenceposition X₀, and the exerciser detecting portion 3000 transmits a signalcorresponding to a current position of the exerciser 1000 measured or acurrent-position measured value X_(r) corresponding thereto to thecontrol portion 7000.

The control portion 7000 calculates a difference between the referenceposition value X₀ and the current-position measured value X_(r) of theexerciser 1000 and transmits a first control signal corresponding to thedifference to the motor driving portion 6000. The motor driving portion6000 controls electrical power supplied from a power supply portion 2500to increase a rotation speed of the driving motor 4000.

When a rotation speed of the driving motor 4000 is increased, a speed ofthe belt 5000 engaged with the driving motor 4000 is increased, whichmoves the exerciser 1000 backward in a direction of the referenceposition X₀.

Similarly, when the exerciser 1000 slowly runs to decelerate from acurrent speed, the current-position measured value X_(r) of theexerciser 1000 is behind the reference position X₀, and the exerciserdetecting portion 3000 transmits a signal corresponding to a currentposition of the exerciser 1000 measured or the current-position measuredvalue X_(r) corresponding thereto to the control portion 7000.

The control portion 7000 calculates a difference between the referenceposition value X₀ and the current-position measured value X_(r) andtransmits the first control signal corresponding to the difference tothe motor driving portion 6000. The motor driving portion 6000 controlselectrical power supplied from the power supply portion 2500 to decreasea rotation speed of the driving motor 4000.

When a rotation speed of the driving motor 4000 is decreased, a speed ofthe belt 5000 engaged with the driving motor 4000 is decreased, whichmoves the exerciser 1000 moves forward in a direction of the referenceposition X₀.

Accordingly, when the exerciser 1000 desires to accelerate ordecelerate, a speed of the belt is automatically controlled so that theexerciser 1000 can be located in the reference position X₀.

A rotation speed of the driving motor 4000 is controlled by the motordriving portion 6000, and torque of the driving motor 4000 istransferred to the roller 2310 engaged with the belt 5000 through thetorque transferring means 2400.

As the driving motor 4000, a direct current (DC) motor or an alternatingcurrent (AC) motor which is usually used may be used. In the exemplaryembodiment of the present invention, an AC motor is used.

The motor driving portion 6000 is supplied with electrical power fromthe power supplying portion 2500 and controls a rotation speed of thedriving motor 4000 in response to the first control signal transmittedfrom the control portion 7000.

The motor driving portion 6000 comprises either of an inverter and aconverter depending on a kind of the driving motor 4000 as shown inFIGS. 4 to 9. In the exemplary embodiment of the present invention, aninverter for supplying an AC current to an AC motor is used.

In the exemplary embodiment of the present invention, the first controlsignal transmitted from the control portion 7000 to the motor drivingportion 6000 is a frequency modulation (FM) signal, and in order toincrease a speed of the driving motor 4000, the first control signalwith a high frequency is generated.

An electrical braking portion 8000 provides a braking torque to thedriving motor 4000 to decelerate the driving motor 4000 when theexerciser 1000 desires to decelerate while walking or running at acertain speed.

When the driving motor 4000 is an AC motor, the electrical brakingportion 8000 may be variously realized by, for example, dynamic braking,regenerative braking, DC braking, single-phase braking, orreversed-phase braking. In the exemplary embodiment of the presentinvention, the electrical braking portion 8000 is realized by thedynamic braking and comprises a resistor which reduces kinetic energy ofthe driving motor 4000 to heat energy.

Even when the driving motor 4000 is a DC motor, the electrical brakingportion 8000 may be realized by, for example, dynamic braking,regenerative braking, or reversed-phase braking.

At this point, since the motor driving portion 6000 has a braking meanscontained therein, the motor driving portion 6000 can provide a firstbraking torque to the driving motor 4000. However, a required brakingtorque exceeds the first braking torque when the electrical brakingportion 8000 is not provided, a trip occurs, as shown in FIG. 1.

For the forgoing reason, the electrical braking portion 8000 generates asecond braking torque to brake the driving motor 4000.

The present invention resolves the above-described problem such thatonly the first braking torque which is a part of a target braking torqueis provided by the motor driving portion 6000 and the rest is providedby the electrical braking portion 8000.

The second braking torque of the electrical braking portion 8000preferably corresponds to a part of the target braking torque whichexceeds the first braking torque. That is, the target braking torqueminus the first braking torque is the second braking torque.

FIGS. 4 to 6 are various circuit diagrams illustrating electricalbraking methods using an AC motor according to the exemplary embodimentof the present inventions. The power supplying portion 2500 forsupplying an AC power, the driving motor 4000, the motor driving portion6000 for controlling a speed of the driving motor 4000, and theelectrical braking portion 8000 for providing a braking torque to thedriving motor 4000 are shown in FIGS. 4 to 6, respectively.

In case where the power supplying portion 2500 supplies an AC power andthe driving motor 4000 is an AC motor, the motor driving portion 6000may comprise a typical inverter.

The inverter comprises a converting portion 6100 for rectifying an ACpower supplied to the motor driving portion 6000, a DC smoothing portion6200 for smoothing a voltage rectified by the converting portion 6100,and an inverting portion 6300 for frequency-modulating a DC powersmoothed by the DC smoothing portion 6200 through the control portion7000 and providing the frequency-modulated power to the driving motor4000. The driving motor 4000 changes its rotation speed depending on afrequency.

When the first control signal for deceleration is transmitted to themotor driving portion 6000 from the control portion 7000 while thedriving motor 4000 is rotating at a certain speed, the kinetic energycorresponding to a difference between a current speed and a deceleratedspeed flows to the motor driving portion 6000 from the driving motor4000 as regenerative energy. Accordingly, the sum of a voltage of thepower supplying portion 2500 and a voltage of the regenerative energy isapplied between both output terminals of the converting portion 6100 orbetween both output terminals of the DC smoothing portion 6200.

FIG. 4 shows that in order to emit the regenerative energy from themotor driving portion 6000, the electrical braking portion 8000 uses abraking resistor 8200 to reduce the regenerative energy to the heatenergy.

A switching portion 8100 of the electrical braking portion 8000 operateswhen a voltage applied between both output terminals of the convertingportion 6100 or between both output terminals of the DC smoothingportion 6200 exceeds a predetermined reference voltage, that is, when abraking torque which exceeds a braking torque (first braking torque) ofthe motor driving portion 4000 is required, so that at least part of theregenerative energy which flows to the motor driving portion 6000 fromthe driving motor 4000 is emitted as the heat energy by the brakingresistor 8200 which comprises a resistor connected between one end ofthe switching portion 8100 and one end of either the converting portion6100 or the DC smoothing portion 6200.

The switching portion 8100 may be configured to operate in response to asecond control signal transmitted from the control portion 7000.

The braking resistor 8200 is preferably designed, corresponding to acapacity of the motor driving portion 6000 and a load applied to thedriving motor 4000, for example, a braking torque (first braking torque)of the motor driving portion 6000 and a maximum target braking torquewhich is a braking torque for providing the target decelerations 210 and220 described in FIG. 1. In the exemplary embodiment of the presentinvention, the motor driving portion 6000 with a capacity of 2.2 KW andthe braking resistor 8200 with a resistance of 50Ω are used.

FIGS. 5 and 6 show that the regenerative energy is sent back to thepower supplying portion 2500 by the electrical braking portion 8000 foremitting the regenerative energy out of the motor driving portion 6000or consuming it.

In FIG. 5, the electrical braking portion 8000 has a similarconfiguration to the inverting portion 6300 of the motor driving portion6000 and is connected between both terminals of the converting portion6100 or between both terminals of the DC smoothing portion 6200.

When a voltage applied between both terminals of the converting portion6100 or between both terminals of the DC smoothing portion 6200 is morethan a predetermined reference voltage due to the regenerative energyflowing into the motor driving portion 6000 from the driving motor 4000,that is, when a braking torque which exceeds a braking torque (firstbraking torque) of the motor driving portion 6000 is required, then theswitching portion 8100 of the electrical braking portion 8000 operatesto transfer the regenerative energy to the power supplying portion 2500.

At this time, a plurality of switching portions 8100 of the electricalbraking portion 8000 are respectively controlled to synchronize a phaseof the regenerative energy with an AC power of the power supplyingportion 2500.

The switching portion 8100 may be configured to be operated by a circuitconfiguration of the inverter 6000 itself or to be operated by thesecond control signal transmitted from the control portion 7000.

In FIG. 6, the regenerative braking similar to that of FIG. 5 is used,but unlike that of FIG. 5, the switching portion 8100 is added to theconverting portion 6100 to serve as the electrical braking portion 8000.

Diodes arranged in the converting portion 6100 or the electrical brakingportion 8000 serve to rectify an AC power of the power supplying portion2500 when a forward power is supplied to the driving motor 4000 from thepower supplying portion 2500, and the switching portion 8100 serves totransfer the regenerative energy to the power supplying portion 2500from the driving motor 4000. The diodes and the switching portion 8100of FIG. 6 are the same in operating principle as those of FIG. 5.

The circuit configurations of FIGS. 4 to 6 according to the exemplaryembodiment of the present invention are described below in more detail.

The power supplying portion 2500 supplies an AC power which is usuallysupplied to home.

The converting portion 6100 is configured by three pairs of diodes forrectifying an AC power supplied from the power supplying portion 2500,and outputs the rectified power through its output terminal.

The DC smoothing portion 6200 is configured by electrically connecting acapacitor to both output terminals of the converting portion 6100 inparallel and serves to smooth the rectified wave form.

The inverting portion 6300 is electrically connected to the outputterminal of the DC smoothing portion 6200 and is configured by threepairs of insulated gate bipolar transistors (IGBTs) in which a switchingelement like a transistor and a diode are connected in parallel. Asignal of a frequency modulator (not shown) for modulating a frequencycorresponding to the first control signal transmitted from the controlportion 7000 is input to gates of the IGBTs, and electrical power of apredetermined frequency is supplied to the driving motor 4000, therebycontrolling a speed of the driving motor 4000.

In case of the DC braking, a braking torque can be provided by blockinga path of from the power supplying portion 2500 to the driving motor4000 and then making a DC current to flow to a primary winding of thedriving motor 4000 in the configurations of FIGS. 4 to 6.

In case of the single phase braking, a braking torque can be provided tothe driving motor by connecting two terminals of a primary winding toeach other and then applying a single-phase AC current between theconnected terminal and the other terminal in the configurations of FIGS.4 to 6.

In case of the reversed-phase braking, a braking torque can be providedto the driving motor 4000 by operating the IGBTs of the invertingportion 6300 to adjust a phase in the configurations of FIGS. 4 to 6.

Here, the electrical braking portion 8000 serves to emit theregenerative energy out of the motor driving portion 6000 or consume itand also serves to provide a braking torque of an opposite direction toa forward torque of the driving motor 4000.

FIGS. 7 to 9 are various circuit diagrams illustrating electricalbraking methods using a DC motor according to the exemplary embodimentof the present invention. The power supplying portion 2500 for supplyingan AC power, the driving motor 4000 which comprises a DC motor in whicha rotation speed is controlled by a voltage difference, the motordriving portion 6000 for controlling a speed of the driving motor 4000,and the electrical braking portion 8000 for providing a braking torqueto the driving motor 4000 are shown in FIGS. 7 to 9, respectively.

In case where the power supplying portion 2500 supplies an AC power andthe driving motor 4000 is a DC motor, the motor driving portion 6000 maycomprise a typical converter.

The converter comprises a converting portion 6110 for rectifying an ACpower flowing to the motor driving portion 6000, and the driving motor4000 comprises an AC field supplying portion connected to an electricalpower source. A rotation speed of the motor driving portion 6000 dependson an average voltage magnitude of a pulse-width modulation wave whichflows in from the motor driving portion 6000.

The power supplying portion 2500 supplies an AC power which is usuallysupplied to home.

The converting portion 6110 comprises three pairs of silicon controlledrectifiers (SCRs) for rectifying an AC power supplied from the powersupplying portion 2500 and outputs the rectified power through itsoutput terminal. The converting portion 6100 controls a switchingelement like a transistor arranged at its output terminal to modulate apulse width in order to control a speed of the driving motor 4000.

When the first control signal for deceleration is transmitted to themotor driving portion 6000 from the control portion 7000 while thedriving motor 4000 is rotating at a certain speed, the kinetic energycorresponding to a difference between a current speed and a deceleratedspeed flows to the motor driving portion 6000 from the driving motor4000 as regenerative energy, so that the sum of a voltage of the powersupplying portion 2500 and a voltage of the regenerative energy isapplied between both output terminals of the converting portion 6110.

FIG. 7 shows that the regenerative energy is reduced to the heat energyby using the electrical braking portion 8000, for example, the brakingresistor 8200.

The switching portion 8100 of the electrical braking portion 8000operates when a voltage applied between both output terminals of theconverting portion 6110 exceeds a predetermined reference voltage, sothat the regenerative energy flowing into the motor driving portion 6000from the driving motor 4000 is reduced to heat energy by the brakingresistor 8200 which comprises a resistor electrically connected betweenone end of the switching portion 8100 and one end of the convertingportion 6110.

Here, the switching portion 8100 may be configured to operate inresponse to the second control signal transmitted from the controlportion 7000.

FIG. 8 shows that the regenerative energy is sent back to the powersupplying portion 2500 by the electrical braking portion 8000 foremitting the regenerative energy out of the motor driving portion 6000or consuming it.

The electrical braking portion 8000 is connected to both ends of theconverting portion 6110 which has a similar configuration of theinverting portion 6300 of the inverter shown in FIGS. 4 to 6.

When a voltage applied between both output terminals of the convertingportion 6110 exceeds a predetermined reference voltage due to theregenerative energy flowing into the motor driving portion 6000 from thedriving motor 4000, the switching portion 8100 of the electrical brakingportion 8000 operates to thereby transfer the regenerative energy to thepower supplying portion 2500.

Here, a plurality of switching portions 8100 of the electrical brakingportion 8000 are respectively controlled to synchronize a phase of theregenerative energy with an AC power of the power supplying portion2500.

The switching portion 8100 may be configured to operate in response to acircuit configuration of the converter itself or operate by the secondcontrol signal transmitted from the control portion 7000.

FIG. 9 shows a reversed-phase braking by using the electrical brakingportion 8000 according to the exemplary embodiment of the presentinvention.

To accelerate the driving motor 4000, the SCRs of the converting portion6110 are turned on, and the SCRs of the electrical braking portion 8000are turned off, so that a voltage of a predetermined polarity issupplied to the driving motor 4000.

To decelerate the driving motor 4000, the SCRs of the converting portion6110 are turned off, and the SCRs of the electrical braking portion 8000are turned on, so that a voltage of an opposite polarity to that foracceleration is supplied to the driving motor 4000 as a braking torque.

As described above, the treadmill of the present invention processes theregenerative energy generated in the driving motor by using theelectrical braking portion, thereby achieving the target braking torque.

Hereinbefore, the electrical braking portion 8000, the motor drivingportion 6000, and the driving motor 4000 have been described focusing ontheir exemplary configuration, but their configuration may be variouslymodified.

Here, the electrical braking portion 8000 means the regenerative energyprocessing portion for emitting the regenerative energy generated in thedriving motor 4000 out of the motor driving portion 6000 or consuming itin order to brake the driving motor 4000, and may comprise the switchingportion 8100 for performing a switching operation for providing thesecond braking torque.

FIGS. 10 to 12 are block diagrams illustrating the control portionaccording to the exemplary embodiment of the present invention.

In FIG. 10, the control portion 7000 computes a measured value X_(r)corresponding to a signal obtained by measuring a position of theexerciser 1000 by the exerciser detecting portion 3000 by using apredetermined criterion and transfers the first control signal to themotor driving portion 6000. The control portion 7000 comprises apre-processing portion 7100, a reference position generating portion7200, and a driving command portion 7300.

FIGS. 10 to 21 show that the measured value X_(r) is transferred to thecontrol portion 7000 from the exerciser detecting portion 3000, but thisis for easy description and is not limited to it.

The measured value X_(r) may be a value corresponding to an exerciserposition generated in the exerciser detecting portion 3000. Also, themeasured value X_(r) may be a value corresponding to an exerciserposition which is converted from a signal transmitted to the controlportion 7000 from the exerciser detecting portion 3000.

In the exemplary embodiment of the present invention described below,the measured value X_(r) means a value generated in the exerciserdetecting portion 3000 and then transferred to the control portion 7000.

The pre-processing portion 7100 processes noise and undesired valuesincluded in the measured value X_(r), which corresponds to a signalobtained by measuring a position of the exerciser 1000, transmitted fromthe exerciser detecting portion 3000 by a data converting criterion togenerate a converted value X_(r)′ and transmits the converted valueX_(r)′ to the reference position generating portion 7200 and/or thedriving command portion 7300.

The pre-processing portion 7100 stores the measured values X_(r−i) (i=0,. . . , n) corresponding to a position of the exerciser 1000 which aremeasured at a unit time interval or the corresponding converted valuesX_(r−i)′ (i=0, . . . , n) processed by the data converting criterion andtransmits the measured values X_(r−i) (i=0, . . . , n) or the convertedvalues X_(r−i)′ (i=0, . . . , n) to the reference position generatingportion 7200 and the driving command portion 7300.

The pre-processing portion 7100 generates a current state value S_(r)which represents which state among an accelerating state, a deceleratingstate and a maintaining state the treadmill is in using a statedetermining criterion based on the measured values X_(r−i) (i=0, . . . ,n) corresponding to a position of the exerciser 1000 which are measuredat a unit time interval or the corresponding converted values X_(r−i)′(i=0, . . . , n) processed by the data converting criterion, andtransmits the current state value S_(r) to the driving command portion7300.

The reference position generating portion 7200 generates a referenceposition value X₀ which is used to determine a difference value with themeasured value X_(r) or the converted value X_(r)′ which corresponds toa current position of the exerciser 1000, and transmits the referenceposition value X₀ to the driving command portion 7300.

Here, the reference position value X₀ means a distance from theexerciser detecting portion 3000 that a driving speed of the drivingmotor 4000 can be constantly maintained when the exerciser 1000 is at apredetermined position.

The reference position generating portion 7200 adjusts the referenceposition value based on a driving speed containing a belt speed or acorresponding speed thereto. Here, the driving speed may be a rotationspeed of the driving motor or a speed corresponding to the rotationspeed, for example, a speed of the belt 5000 or the first controlsignal, transmitted to the motor driving portion 6000 from the controlportion 7000.

The driving command portion 7300 computes a difference value ΔX betweenthe reference position value X₀ transmitted from the reference positiongenerating portion 7200 and the measured value X_(r) corresponding to aposition of the exerciser 1000 or the converted value X_(r)′ transmittedfrom the pre-processing portion 7100 to transmit the first controlsignal for controlling a speed of the driving motor 4000 to the motordriving portion 6000.

In the exemplary embodiment of the present invention, the convertedvalue X_(r)′ transmitted from the pre-processing portion 7100 is used inorder to obtain the difference value ΔX with the reference positionvalue X₀.

The driving command portion 7300 performs a closed-loop control andconverts control constants contained in a control equation for aclosed-loop control to adjust a control gain, thereby controlling acontrol sensitivity.

FIG. 11 is a detailed block diagram illustrating the pre-processingportion shown in FIG. 10. The pre-processing portion 7100 comprises astate determining portion 7110, a data converting portion 7120, and adata storing portion 7130.

The state determining portion 7110 determines which state among theaccelerating state, the decelerating state and the maintaining state theexerciser 1000 is in using the state determining criterion and generatesthe current state value S_(r) corresponding to a current state of theexerciser 1000.

The data converting portion 7120 processes noise and undesired valuesincluded in the measured values X_(r) which correspond to a signaltransmitted from the exerciser detecting portion 3000 using the dataconverting criterion to generate the converted value X_(r)′.

The data storing portion 7130 stores the measured values X_(r−i) (i=0, .. . , n) which are measured at a unit time interval or the convertedvalues X_(r−i)′ (i=0, . . . , n) which are generated at a unit-timeinterval by the data converting portion 7120. The data storing portion7130 may store the state values S_(r−i) (i=0, . . . , n) which aregenerated at a unit time interval in the state determining portion 7110.

In more detail, the state determining portion 7110 compares the currentmeasured value X_(r) containing noise and undesired data transmittedfrom the exerciser detecting portion 3000 to the past values X_(r−i)^(T) (i=1, . . . , n) stored in the data storing portion 7130 todetermine the current state using the state determining criterion,thereby generating the current state value S_(r) which is one of theaccelerating state, the decelerating state or the mainlining state.

In an exemplary embodiment of the present invention, the past convertedvalues X_(r−i)′ (i=1, . . . , n) are used as the past values X_(r−i)^(T) (i=1, . . . , n) to be compared to the current measured value X_(r)to generate the current state value S_(r).

The generated current state value S_(r) may be stored in the datastoring portion 7130 or may be transmitted to the driving commandportion 7300 to be used to generate the first control signal.

In more detail, the data converting portion 7120 determines a forward orbackward direction of the exerciser 1000 based on the past valuesX_(r−i) ^(T) (i=1, . . . , n) and the current measured value X_(r) togenerate the current converted value X_(r)′.

In the exemplary embodiment of the present invention, the past convertedvalues X_(r−i)′ (i=1, . . . , n) are used as the past values X_(r−i)^(T) (i=1, . . . , n) to be compared to the current measured value X_(r)to generate the current converted value X_(r)′.

The current converted value X_(r)′ generated is stored in the datastoring portion 7130 for a comparison for generating the converted valueX_(r+i)′ of the measured value X_(r+1) of the next unit time and istransmitted to the driving command portion 7300 to be used to computethe position difference value ΔX which is a difference with thereference position value X₀. Also, the current converted value X_(r)′may be transmitted to the reference position generating portion 7200 tobe used to generate the reference position value X₀.

FIG. 12 is a detailed block diagram illustrating the driving commandportion 7300 shown in FIG. 10. The driving command portion 7300comprises a control gain portion 7310, a sensitivity adjusting portion7320, a control signal generating portion 7330.

The control gain portion 7310 generates a control gain ΔV correspondingto a speed by applying the position difference value ΔX which is adifference between the reference position value X₀ transmitted from thereference position generating portion 7200 and the current value X_(r)^(T), for example, the current converted value X_(r)′ transmitted fromthe pre-processing portion 7100 to a PI control of Equation 1 or a PIDcontrol of Equation 2

$\begin{matrix}{{\Delta \; V_{j}} = {{K_{p}\Delta \; X_{j}} + {K_{i}{\int_{0}^{j}{\Delta \; X_{t}{t}}}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack \\{{\Delta \; V_{j}} = {{K_{p}\Delta \; X_{j}} + {K_{i}{\int_{0}^{j}{\Delta \; X_{t}{t}}}} + {K_{d}\frac{{\Delta}\; X_{j}}{t}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Here, a proportional constant K_(p), an integral constant K₁, and adifferential constant K_(d) which are used as control constants areadjusted by the sensitivity adjusting portion 7320 in order to acceptvarious exercising patterns of the exerciser 1000.

In the exemplary embodiment of the present invention, an experiment hasbeen performed by using a PI control, which is fast in response speedand small in target value error, expressed by Equation 1, but othercontrol methods can be used.

The control signal generating portion 7330 generates the first controlsignal for controlling a speed of the driving motor 4000 through themotor driving portion 6000 based on the control gain ΔV transmitted fromthe control gain portion 7310 and transmits the first control signal tothe motor driving portion 6000.

The sensitivity adjusting portion 7320 changes the values of the controlconstants used in the control gain portion 7310 in consideration ofvarious exercising patterns of the exerciser 1000 to adjust thesensitivity of a speed response of the belt to movement of the exerciser1000.

The respective components 7100, 7200 and 7300 contained in the controlportion 7000 may be respectively configured in separate physical spacesor may be configured by a program code in a single physical space.

FIG. 13 is a flowchart illustrating a control method of the controlportion 7000 according to the exemplary embodiment of the presentinvention. The control method of the control portion 7000 comprises aposition measuring step S1000 for the exerciser detecting portion 3000measuring a position of the exerciser, a pre-processing step S2000 forthe control portion 7000 receiving a measured signal or a correspondingmeasured value X_(r) and converting the measured value X_(r) to theconverted value X_(r)′ by the pre-processing procedure, a referenceposition generating step S3000 for generating the reference positionvalue X₀ based on the driving speed, which can include the belt speed ora speed corresponding to the belt speed, and a driving command stepS4000 for transmitting the first control signal to the motor drivingportion 6000 based on either of the measured value X_(r) and theconverted value X_(r)′ and the reference position value X₀ to perform adriving command.

The pre-processing step S2000 comprises a state determining step S2100for determining a current state of the exerciser and a data convertingstep S2200 for converting the measured value X_(r) to the convertedvalue X_(r)′.

The driving command step S4000 comprises a sensitivity adjusting stepS4100 for determining the driving speed containing the belt speed or thespeed corresponding to the belt speed or a position change rate of theexerciser to adjust the control constant, a control gain generating stepS4200 for generating the control gain by the closed-loop controlequation, and a control signal generating step S4300 for transmitting acommand to the motor driving portion 6000 based on the control gain.

FIG. 14 is a flowchart illustrating an operation of the statedetermining portion according to the exemplary embodiment of the presentinvention. In the flowchart of FIG. 14, the portion marked as “(a)”shows steps according to performed functions, and the portion marked“(b)” shows a determining criterion of each step in the portion “(a)”.

The state determining step S2100 includes a data direction determiningstep S2110 for determining a forward or backward direction in which themeasured value X_(r) or the converted value X_(r)′ obtained at aunit-time interval changes with respect to an immediately previous orprevious measured value or an immediately previous or previous convertedvalue, that is, for determining a data direction corresponding to aforward or backward direction in which a subsequent data value amongdata values X_(r−i) ^(o) (i=0, . . . , n) changes in with respect to apreceding data value; an acceleration/deceleration magnitude referencecomparing step S2120 for determining whether a difference between ameasured value or converted value of a predetermined previous unit timewhich is used as a reference value, for example, a preceding data valueof a predetermined previous unit time which is used as a reference valueand a current measured value or current converted value satisfies apredetermined criterion C_(a) or C_(d) or not; and a state determiningstep S2130 for finally determining the current state.

The state determining step S2130 may further include a step forgenerating a state value S_(r) by using a value corresponding to thecurrent exerciser state.

The data direction determining step S2110 uses the past values X_(r−i)^(T) (i=1, . . . , n) stored in the data storing portion 7130 and thecurrent value X_(r) ^(T). Here, an immediately previously occurringconverted value and earlier previous converted values are used as thepast values X_(r−i) ^(T) (i=1, . . . , n), and the current measuredvalue Xr is used as the current value X_(r) ^(T). If the past valuesX_(r−i) ^(T) (i=1, . . . , n) and the current value X_(r) ^(T) comprisesonly of a continuous forward direction or a maintaining direction andthe difference between the past value X_(r−j) ^(T) (j is a positiveinteger) of the predetermined previous unit time and the current valueX_(r) ^(T) results in a forward direction, then the procedure goes to anacceleration magnitude reference comparing step S2121. That is, if thesubsequent data value among the data values X_(r−i) ^(o) (i=0, . . . ,n) is configured to be a continuous forward direction or a maintainingdirection with respect to the preceding data value only, and the currentvalue X_(r) ^(T), has a data direction (which is either a continuousforward direction or a maintaining direction with respect to thepreceding data value) which is a forward direction, then the proceduregoes to the acceleration magnitude reference comparing step S2121.

Also, if the past values X_(r−i) ^(T) (i=1, . . . , n) and the currentvalue X_(r) ^(T) are configured as a continuous backward direction ormaintaining direction and a difference between the past value X_(r−j)^(T) (j is a positive integer) of the predetermined previous unit timeand the current value X_(r) ^(T) results in a backward direction, thenthe procedure goes to a deceleration magnitude reference comparing stepS2122. That is, if the subsequent data value among the data valuesX_(r−i) ^(o) (i=0, . . . , n) comprises only of a continuous backwarddirection or a maintaining direction with respect to the preceding datavalue, and the current value X_(r) ^(T) has a data direction (which isgenerated as either a backward direction or a maintaining direction withrespect to the preceding data value) is a backward direction, then theprocedure goes to the deceleration magnitude reference comparing stepS2122.

Further, if the data values X_(r−i) ^(o) (i=0, . . . , n) do not have acontinuous direction, that is, a forward direction and a backwarddirection exist together in the data values X_(r−i) ^(o) (i=0, . . . ,n) or the data values X_(r−i) ^(o) (i=0, . . . , n) have a continuousmaintaining direction, then the procedure does not go to theacceleration/deceleration magnitude reference comparing step S2120, andin the state determining step S2130, the current sate is determined as amaintaining state (step S2132).

Preferably, the data direction is determined by using the past valuesX_(r−i)′ (i=1, 2, 3) of at least 3 previously occurring unit timesimmediately before the current unit time, for example, the valuesX_(r−i)′ (i=1, . . . , n) where n is equal to or more than 3, as thepast values X_(r−i) ^(T) (i=1, . . . , n) and the current measured valueX_(r) as the current value X_(r) ^(T).

In the acceleration magnitude reference comparing step S2121 of theacceleration/deceleration magnitude reference comparing step S2120, whena data direction is determined as a forward direction in the datadirection determining step S2111, it is determined whether a differencevalue between a past value X_(r−j) ^(T) (j is a positive integer) of apredetermined previous unit time and a current value X_(r) ^(T) exceedsthe predetermined acceleration magnitude reference value C_(a) or not(step S2121). If the difference value exceeds the predeterminedacceleration magnitude reference value C_(a), then the current state isdetermined as an acceleration state (step S2131). If the differencevalue is equal to or less than a predetermined acceleration magnitudereference value C_(a), then the current state is determined as amaintaining state (step S2132).

When a data direction is determined as a backward direction in the datadirection determining step S2111, in the deceleration magnitudereference comparing step S2122, it is determined whether a differencevalue between a past value X_(r−j) ^(T) (j is a positive integer) of apredetermined previous unit time and a current value X_(r) ^(T) exceedsa predetermined deceleration magnitude reference value C_(d) or not(step S2122). If the difference value exceeds the predetermineddeceleration magnitude reference value C_(d), then the current state isdetermined as a deceleration state (step S2133), and if the differencevalue is equal to or less than the predetermined deceleration magnitudereference value C_(d), then the current state is determined as amaintaining state (step S2132).

The data direction is determined by using preferably the past valueX_(r−2) ^(T) of an at least second most recent or earlier previous unittime from the current unit time, more preferably the past value X_(r−3)^(T) of a third most recent previous unit time as the past value X_(r−j)^(T) (j is a positive integer) of a predetermined previous unit time tobe compared in difference with the current measured value X_(r), and thecurrent measured value X_(r) as the current value X_(r) ^(T).

Also, the state determining step S2130 may further include a step forgenerating an accelerating state, a maintaining state or a deceleratingstate as the current state S_(r). The generated current state S_(r) maybe stored in the data storing portion 7130 or may be used in the drivingcommand portion 7300.

FIG. 15 is a flowchart illustrating an operation of the data convertingportion according to the exemplary embodiment of the present invention.In the flowchart of FIG. 15, the portion marked “(a)” shows stepsaccording to performed functions, and the portion marked “(b)” shows adetermining criterion of each step in the portion “(a)”.

The data converting step S2200 includes a past data directiondetermining step S2210 for determining a direction in which the pastvalues X_(r−i) ^(T) (i=1, . . . , n) change, a current data directiondetermining step S2220 for determining a direction of the currentmeasured value X_(r) relative to the immediately previous past valueX_(r−1) ^(T), and a converted value generating step S2230 forconverting/generating the current measured value X_(r) into the currentconverted value X_(r)′.

The converted value generating step S2240 may further include a step forconverting a weighted average value of a converted value X_(r)′ onceconverted by the above step and the past values X_(r−i) ^(T) (i=1, . . ., n) predetermined unit times (n) into the current converted valueX_(r)′.

The past data direction determining step S2210 determines whether thepast values X_(r−i) ^(T) (i=1, . . . , n) continuously results in aforward direction or a maintaining direction or continuously results ina backward direction or a maintaining direction using the past valuesX_(r−i) ^(T) (i=1, . . . , n) of from a predetermined previous unit time(n), and determines whether there exists a constant direction that adifference with the past value X_(r−n) ^(T) of the predeterminedprevious unit time is generated in a forward direction or a backwarddirection or not (step S2211).

If it is determined in the past data direction determining step S2210that there is no constant direction, e.g., since the past values X_(r−i)^(T) (i=1, . . . , n) have only a maintaining direction (i.e., samevalues), or have a forward direction and a backward direction together,then the current converted value X_(r)′ is generated in the convertedvalue generating step S2230 using the current measured value X_(r)without going to the current data direction determining step S2220 (stepS2232). In this instance, the current measured X_(r) is used as thecurrent converted value X_(r)′.

If it is determined in the past data direction determining step S2210that a constant direction exists, e.g., since the past values X_(r−i)^(T) (i=1, . . . , n) continuously results in a forward direction or amaintaining direction or continuously results in a backward direction ora maintaining direction and a difference with the past value

X_(r−n) ^(T) of a predetermined previous unit time (n) also results in aforward direction or a backward direction, then the procedure goes tothe current data direction determining step S2220.

In the exemplary embodiment of the present invention, the past valuesX_(r−i)′ (i=1, 2, 3) of 3 previously occurring unit times immediatelybefore the current unit time are used as the past values X_(r−i) ^(T)(i=1, . . . , n) used in the past data direction determining step S2210.

The current data determining step S2220 determines whether the currentvalue (current measured value) maintains a direction of the past data(past converted value) determined by the past data direction determiningstep S2210 or not. In cases where the past values X_(r−i) ^(T) (i=1, . .. , n) have a forward direction which has a continuous forward directionor maintaining direction, if the current value (current measured value)changes in a backward direction compared to the immediately previouspast value X_(r−1) ^(T), then the current converted value X_(r)′ isgenerated by restricting the current measured value X_(r) (step S2231)in the converted value generating step S2230.

Similarly, in case where the past values X_(r−i) ^(T) (i=1, . . . , n)have a backward direction which has a continuous backward direction ormaintaining direction, if the current value (current measured value)changes in a forward direction compared to the immediately previous pastvalue X_(r−1) ^(T), then the current converted value X_(r)′ is generatedby restricting the current measured value X_(r) (step S2231) in theconverted value generating step S2230.

That is, it is determined whether a direction of the current value(current measured value) changes with respect to the past values X_(r−i)^(T) (i=1, . . . , n) or not (step S2221). If it changes, in theconverted value generating step S2230, the current measured value X_(r)is restricted to generate the current converted value X_(r)′ (stepS2231), whereas if it does not change, the current converted valueX_(r)′ is generated by using the current measured value X_(r) (stepS2232).

This is done because it is physically impossible for the exerciser tochange to a deceleration state immediately from an acceleration state orto an acceleration state immediately from a deceleration state. Thus,the current measured value X_(r) is converted into the current convertedvalue X_(r)′ which is a physically possible value for the current valueX_(r) ^(T).

In addition to the determining steps and the determining criterions ofFIG. 15, if based on the past values X_(r−i) ^(T) (i=1, . . . , n) offrom a predetermined previous unit time (n) and the current value(current measured value), it is determined that the past values

X_(r−i) ^(T) (i=1, . . . , n) from a predetermined previous unit time(n) and the current value (current measured value) continuously haveonly a forward direction or a maintaining direction or continuously haveonly a backward direction or a maintaining direction and a differencewith the pas value X_(r−n) ^(T) of the predetermined previous unit time(n) generates a forward direction or a backward direction, then thecurrent measured value X_(r) may be used to generate the currentconverted value X_(r)′ (step S2232). Otherwise, that is, if a forwarddirection and a backward direction exist together, then the currentmeasured value X_(r) may be restricted to generate the current convertedvalue X_(r)′ (step S2231).

In the step S2231 of the converted value generating step S2230 forrestricting the current measured value X_(r) to generate the currentconverted value X_(r)′, the past value X_(r−1) ^(T) of a first, mostrecent previous unit time which is the immediately previous unit time ispreferably used as the current converted value X_(r)′.

After generating the current converted value X_(r)′ as described above,the current converted value X_(r)′ may be used in a subsequent controlprocedure “as is” but in order to prevent the current converted valueX_(r)′ from greatly changing from the immediately previous convertedvalue X_(r−1)′, the procedure may further include a weight-averagingstep for generating a final converted value X_(r)′ by weight-averagingthe past values X_(r−i)′ (i=1, . . . , k) of predetermined unit times(k) and the current converted value X_(r)′.

The past converted values X_(r−1)′ (i=1, 2, 3) of 3 (first to third)previous unit times are to preferably used as the past converted valuesX_(r−i)′ for a weight average.

FIG. 16 is a flowchart illustrating an operation of the data convertingportion according to another exemplary embodiment of the presentinvention.

Hereinafter, a term “a normal range reference N_(r)” includes anacceleration normal range reference N_(a) and a deceleration normalrange reference N_(d). The normal range reference N_(r) means areference for determining whether the current measured value is normalor not based on a difference with the past value X_(r−k) ^(T) (k is apositive integer) of a predetermined previous unit time (k).

The data converting step S2200 of FIG. 16 includes a normal rangecontrol step S2240, a normal range determining step S2250, and aconverted value generating step S2260.

In the normal range determining step S2250, a result of a function usingthe current measured value X_(r) and/or the past value X_(r−k) ^(T) (kis a positive integer) of a predetermined previous unit time (k) iscompared to the normal range reference N_(r).

In the normal range determining step S2250, it is determined whether adifference between the current measured value X_(r) and the past valueX_(r−k) ^(T) (k is a positive integer) of a predetermined previous unittime (k) is in the normal range reference N_(r) or not (step S2251). Ifthe difference is in the normal range reference N₁, the currentconverted value X_(r)′ is generated by using the current measured valueX_(r) “as is” (step S2261), whereas if the difference is not in thenormal range reference N_(r), the current converted value X_(r)′ isgenerated by restricting the current measured value X_(r) (step S2262).

If the difference between the current measured value X_(r) and the pastvalue X_(r−k) ^(T) (k is a positive integer) of a predetermined previousunit time (k) is not in the normal range reference N_(r), a count (i, iis an integer) with a predetermined initial value is increased by 1(i=i+1) (step S2253), whereas if the difference is in the normal rangereference N_(r), the count (i) is reset to the initial value (stepS2252). The initial value of the count (i) is preferably set to zero(0).

In the normal range control step S2240, the normal range reference isadjusted, maintained or initialized by comparing the count (i) (stepS2241).

In more detail, if the count (i) is larger than the initial value and isequal to or less than a predetermined reference (n, n is an integer),the normal range reference N_(r) is adjusted (step S2242). Preferably,an absolute value of the normal range reference N_(r) is adjusted. Inthe below description, the normal range reference N_(r) will bedescribed focusing on the deceleration normal range reference N_(d), andthe acceleration normal range reference N_(a) will be easily understoodfrom the description by reversing a sign by a person skilled in the art.

The normal range reference N_(r) may be adjusted by using the samechange magnitude or difference change magnitudes.

If the count (i) has the initial value, the normal range reference N_(r)is initialized (step S2243), and if the count (i) is larger than thepredetermined reference (n), the normal range reference N_(r) ismaintained (step S2244).

The normal range reference N_(r) corresponding to the predeterminedreference (n), i.e., a maximum value of the normal range reference N_(r)is preferably set to correspond to a magnitude of a position changegenerated by an exerciser with an excellent exercising ability, and thenormal range reference N_(r) of when the count (i) has the initialvalue, i.e., an initial value of the normal range reference N_(r) ispreferably set to be equal to or less than the maximum value of normalrange reference N_(r).

The acceleration normal range reference N_(a) and the decelerationnormal range reference N_(d) may have the same value or differencevalues from each other. For example, in the normal range determiningstep S2250, if a change of the current measured value X_(r) to the pastvalue X_(r−k) ^(T) (k is a positive integer) of a predetermined previousunit time (k) has a forward direction, the acceleration normal rangereference N_(a) may be applied as the normal range reference N_(r),whereas if a change of the current measured value X_(r) to the pastvalue X_(r−k) ^(T) (k is a positive integer) of a predetermined previousunit time (k) has a backward direction, the deceleration normal rangereference N_(d) may be applied as the normal range reference N_(r).

In the exemplary embodiment of the present invention, the accelerationnormal range reference N_(a) and the deceleration normal range referenceN_(d) have different values from each other.

The predetermined reference (n) to be compared with the count (i) when achange of the current measured value X_(r) to the past value X_(r−k)^(T) (k is a positive integer) of a predetermined previous unit time (k)has a forward direction may have the same value as or may have adifferent value from when a change of the current measured value X_(r)to the past value X_(r−k) ^(T) (k is a positive integer) of apredetermined previous unit time (k) has a backward direction. In theexemplary embodiment of the present invention, the predeterminedreference (n) to be compared with the count (i) when a change of thecurrent measured value X_(r) to the past value X_(r−k) ^(T) (k is apositive integer) of a predetermined previous unit time (k) has aforward direction has a different value from when a change of thecurrent measured value X_(r) to the past value X_(r−k) ^(T) (k is apositive integer) of a predetermined previous unit time (k) has abackward direction.

In the exemplary embodiment of the present invention, in the step S2262of the converted value generating step S2260 for restricting the currentmeasured value X_(r) to generate the current converted value X_(r)′, avalue obtained by adding the normal range reference N_(r) to the pastvalue X_(r−k) ^(T) (k is a positive integer) of a predetermined previousunit time (k) is generated as the current converted value X_(r)′.

That is, when the current measured value X_(r) exceeds the normal rangereference N_(r) with respect to the past value X_(r−k) ^(T) (k is apositive integer) of a predetermined previous unit time (k), the currentconverted X_(r)′ is generated by restricting the current measured valueX_(r) such that the normal range reference N_(r) is set as a changelimit of the current converted value X_(r)′ with respect to the pastvalue X_(r−k) ^(T) (k is a positive integer) of a predetermined previousunit time (k).

Of course, a value which is equal to or smaller than a value obtained byadding the normal range reference N_(r) to the past value X_(r−k) ^(T)(k is a positive integer) of a predetermined previous unit time (k) maybe generated as the current converted value X_(r)′.

In the exemplary embodiment of the present invention, the immediatelyprevious past value X_(r−1) ^(T), for example, the past value of thefirst most recent previous unit time (k=1) is used as the past valueX_(r−k) ^(T) (k is a positive integer) of a predetermined previous unittime (k) used to determine whether the current measured value X_(r)exceeds the normal range reference N_(r) or not.

After generating the current converted value X; as described above, thecurrent converted value may be used in a subsequent control procedure“as is” but in order to prevent the current converted value X_(r)′ fromgreatly changing from the immediately previous converted value X_(r−1)′,the procedure may further include a weight-averaging step for generatinga final converted value X_(r)′ by weight-averaging the past valuesX_(r−i)′ (i=1, . . . , k) of predetermined unit times and the currentconverted value X_(r)′ obtained by the above procedure.

The past converted values X_(r−1)′ (i=1, 2, 3) of 3 (first to third)previous unit times are preferably used as the past converted valuesX_(r−i)′ for a weight average.

Each step and a combination relationship between the respective steps ofFIG. 16 may be variously modified by a person skilled in the art.

Also, a person skilled in the art can sufficiently understand that thenormal range reference of FIG. 16 can be applied to the flowchart ofFIG. 15.

For example, in the converted value generating step S2230, the stepS2232 for using the current measured value X_(r) to generate the currentconverted value X_(r)′ shown in FIG. 15 may be replaced with the stepfor determining the normal range reference N_(r) shown in FIG. 16.

FIG. 17 is a flowchart illustrating an operation of the referenceposition generating portion according to the exemplary embodiment of thepresent invention, which includes a belt speed determining step S3010for determining a speed of the driving belt and a reference positionvalue adjusting step S3020 for adjusting and generating a referenceposition corresponding to the speed.

The belt speed determining step S3010 is a step for determining adriving speed containing a belt speed or a speed corresponding to thebelt speed which is to be transferred to the reference positiongenerating portion 7200. The driving speed may be computed using thefirst control signal transmitted to the motor driving portion 6000 fromthe control portion 7000 or using a signal transmitted to the drivingmotor 4000 from the motor driving portion 6000.

The driving speed may be computed by measuring a rotation speed of thedriving motor 4000 or the roller 2310 or by directly measuring a movingspeed of the driving belt 5000.

In the reference position value adjusting step S3020, the referenceposition value X₀ is decreased if the driving speed is fast, whereas thereference position value X₀ is increased if the driving speed is slow.

While the exerciser 1000 exercises at a low speed, the referenceposition value X₀ is set to be far from the exerciser detecting portion3000 in order to achieve a fast acceleration, whereas while theexerciser 1000 exercises at a high speed, the reference position valueX₀ is set to be short from the exerciser detecting portion 3000 in orderto achieve a fast deceleration.

That is, the reference position value X₀ is variably controlleddepending on a speed of the driving belt such that the referenceposition value X₀ is increased if the driving speed is slow and thereference position value X₀ is decreased if the driving speed is fast.

Also, based upon a moving direction of a top surface of the belt whichsupports the exerciser, the reference position value X₀ is set to beshort from a start point of the belt if the driving speed is fast, andthe reference position value X₀ is set to be far from the start point ofthe belt if the driving speed is slow.

A range in which the reference position value X₀ is varied preferablycorresponds to a distance of from the start point to the end point in amoving direction of the top surface of the belt. That is, a range inwhich the reference position value X₀ is varied is preferably less thanthe length of the top surface of the belt.

More preferably, a range in which the reference position value X₀ isvaried is separated by a predetermined distance from the start point andthe end point of the top surface of the belt. This is because when thereference position value X₀ which is a reference for causingacceleration or deceleration by using a difference with the currentposition of the exerciser is too close to the start point or the endpoint of the top surface of the belt, then the risk to the exerciser mayincrease.

FIG. 18 is a graph illustrating a method for restricting a maximumacceleration/deceleration according to the exemplary embodiment of thepresent invention.

A maximum acceleration/deceleration is restricted depending on a speedto the extent that can prevent the treadmill from applying anacceleration/deceleration that is difficult for the exerciser 1000 toreact to, thereby reducing injury risk for the exerciser 1000.

Also, an abrupt acceleration/deceleration in a low speed section maycause the exerciser to feel uncomfortable and may be risky. But, atreadmill needs to rapidly follow the exerciser'sacceleration/deceleration intent in a high speed section. For theforegoing reasons, a maximum acceleration/deceleration is restricteddepending on a speed.

As shown in FIG. 1, in case of a low speed, since the areas A-a and B-a,in which a deceleration is larger than the upper target deceleration220, may pose risk to the exerciser as can bee seen by the targetdeceleration line segments 210 and 220, the maximum deceleration is thuspreferably set to a value equal to or less than the upper targetdeceleration 220. In case of a high speed, since the upper targetdeceleration 220 is large, the maximum deceleration of a high speed isthus preferably set to a larger value than that of a low speed.

Even though it depends on the exerciser's exercising ability, theexerciser can exercise with a good exercising feeling with adeceleration of up to the target deceleration corresponding to thedriving speed containing the belt speed or a speed corresponding to thebelt speed, but the exerciser may feel uncomfortable or fall down in anabrupt deceleration of more than the target deceleration.

The experiment according to the exemplary embodiment of the presentinvention shows that the upper target deceleration 220 is about 2.5 km/hper second when the driving speed is a low speed of 5 km/h, and theupper target deceleration 220 is about 9.5 km/h per second when thedriving speed is a high speed of 19 km/h.

Therefore, it is preferred that the maximum deceleration is restrictedto a large value if the driving speed is fast and to a small value ifthe driving speed is slow.

A similar principle can be applied to a restriction of the maximumacceleration depending on the driving speed.

The driving speed can be computed or measured by the various methodsdescribed in FIG. 17, and the maximum acceleration and the maximumdeceleration are adjusted depending on the speed.

In a low speed section in which the driving speed is slow, the maximumacceleration and/or the maximum deceleration are set to a small value,and in a high speed section in which the driving speed is fast, themaximum acceleration and/or the maximum deceleration are set to a largevalue.

Also, in a middle speed section which the driving speed is not fast norslow, the maximum acceleration and/or the maximum deceleration areincreased as the driving speed is increased.

Such a restriction of the maximum acceleration/deceleration depending onthe driving speed is performed by the driving command portion 7300 ofthe control portion 7000, preferably by the control signal generatingportion 7330.

The control signal generating portion 7330 restricts the first controlsignal to be output, based on the driving speed and a control gain ΔVwhich is a signal corresponding to an acceleration/decelerationgenerated in the control gain portion 7310.

FIGS. 19 and 20 are flowcharts illustrating an operation of thesensitivity adjusting portion according to the exemplary embodiment ofthe present invention.

A control sensitivity which will be described below is computed based ona difference value between the reference position value and the datavalue and means a sensitivity of a control gain for generating thecontrol signal. When a control sensitivity is large, a control gain islarger, compared to when a control sensitivity is small.

That is, the control sensitivity means a response degree to the controlgain output by using the difference value as an input variable.

An expression that the control sensitivity is large, high or sensitivemeans that the response degree of the control gain which is a result ofthe difference value as an input variable is large. An expression thatthe control sensitivity is small, low or insensitive means that theresponse degree of the control gain which is a result of the differencevalue as an input variable is small.

FIG. 19 is a flowchart illustrating a sensitivity adjusting methodperformed by the sensitivity adjusting portion according to theexemplary embodiment of the present invention. The sensitivity adjustingmethod of FIG. 19 includes a current position determining step S4110 fordetermining whether the exerciser 1000 is located in a stable sectionX_(s) or not, a state determining step S4120 for determining a currentstate of the exerciser 1000 corresponding to a current state value ofthe exerciser generated by the state determining portion 7110, a perioddetermining step S4130 for determining whether the exerciser 1000 staysin the stable section X_(s) during a predetermined time period or not,and a control sensitivity adjusting step S4140 for adjusting a controlsensitivity when the exerciser 1000 stays in the stable section X_(s)during a predetermined time period.

The stable section X_(s) represents a predetermined area rangecontaining the reference position value X₀. When the measured valueX_(r) or the converted value X_(r)′ corresponding to the position of theexerciser 1000 is in a range of the stable section X_(s), the controlsensitivity is lowered or the previous first control signal is notchanged so that the exerciser 1000 can maintain the speed.

In the current position determining step S4110, it is determined whetheror not the current value X_(r) ^(T) corresponding to the currentposition of the exerciser 1000 is in a range of the stable section X_(s)containing a predetermined area range (step S4111). If the current valueX_(r) ^(T) is in a range of the stable section X_(s) the procedure goesto the state determining step S4120, whereas if the current value X_(r)^(T) is not in a range of the stable section X_(s), a count isinitialized (in the exemplary embodiment of the present invention, aninitial count is “zero”) (step S4122), and then the procedure goes tothe speed change section control sensitivity applying step S4142 whichwill be described in detail with reference to FIG. 20 and/or Equation 3.

In the state determining step S4120, the current state value S_(r) ofthe exerciser determined by performing the state determining method ofFIG. 14 is received from the state determining portion 7110 or the datastoring portion 7130 of the pre-processing portion 7100, and it isdetermined whether the current state S_(r) is an accelerating state or adecelerating state.

At this time, if the current state value S_(r) is either of anaccelerating state and a decelerating state (step S4122), the count isreset (i=0), and then the speed change section control sensitivityadjusting step S4142 which will be described with reference to FIG. 20and/or Equation 3 is performed. If the current state value S_(r) isneither of an accelerating state and a decelerating state, the perioddetermining step S4130 is performed.

In the period determining step S4130, a count (i) with a predeterminedinitial value is increased by one (1) (i=i+1) (step S4131), and it isdetermined whether the count is equal to or greater than a predeterminedreference (k) or not (step S4132). If the count is equal to or greaterthan the predetermined reference (k), a stable section controlsensitivity applying step S4141 is performed to apply a stable sectioncontrol sensitivity as a control sensitivity of the control gain portion7310, whereas if the count is smaller than the predetermined reference(k), a speed change section control sensitivity applying step S4142which will be described with reference to FIG. 20 and/or Equation 3 isperformed. Preferably, “zero” is used as an initial value of the count(i).

In the stable section control sensitivity applying step S4141 of thecontrol sensitivity adjusting step S4140, a control constant in acontrol equation of the control gain portion 7310 is adjusted to lowerthe control sensitivity, so that a speed change sensitivity of the beltwith respect to a position change of the exerciser 1000 is lowered,satisfying a speed maintaining intend of the exerciser 1000.

In the exemplary embodiment of the present invention, the reference (k)used in the step S4131 for determining whether the count (i) is equal toor greater than the predetermined reference (k) is set to five (5). Thatis, when the current value X_(r) ^(T) exists in the stable section X_(s)equal to or more than five (5) times, it is determined as the speedmaintaining intend of the exerciser 1000, so that the control constantis adjusted to lower the control sensitivity.

A relationship between the control constant and the control sensitivityand a method for adjusting the control sensitivity to adjust the controlsensitivity will be explained later with reference to Equation 3.

FIG. 20 is a flowchart illustrating a control sensitivity adjustingmethod according to the exemplary embodiment of the present invention.The control sensitivity adjusting method of FIG. 20 includes a currentstate determining step S4150 for determining whether the current stateis an accelerating state or a decelerating state, a speed/change ratedetermining step S4160 for determining a driving speed containing a beltspeed or a corresponding speed thereto or an exerciser position changerate, and a control sensitivity adjusting step S4160 for adjusting acontrol sensitivity according to the determined speed/change rate. Thecontrol sensitivity adjusting method of FIG. 20 may further include acontrol gain adjusting step S4210 for computing a control gain obtainedby a control equation that a control sensitivity is adjusted and finallyadjusting a control gain.

In the current state determining step S4150, it is determined whether ornot the current state value S_(r) generated in the state determiningportion 7110 is a value corresponding to either of an accelerating stateand a decelerating state (step S4151). If the current state is either ofan accelerating state and a decelerating state, the speed/change ratedetermining step S4160 is performed, whereas if the current state isneither of an accelerating state and a decelerating state, the controlsensitivity is adjusted in a stable section control sensitivity applyingstep S4173 corresponding to a stable section which is described withreference to FIG. 19 and Equation 3.

The speed/change rate determining step S4160 includes two steps. One isan exerciser position change rate determining step S4161 for determininga change rate per unit time of the measure value X_(r−i) (i=0, . . . ,n) or the converted values X_(r−i)′ (i=0, . . . , n), and the other is adriving speed determining step S4162.

The exerciser position change rate determining step S4161 is todetermine an accelerating or decelerating trend of the exerciser 1000. Achange rate per unit of the converted values X_(r−i)′ (i=0, . . . , n)is determined to determine a forward or backward speed.

The exerciser can change position by accelerating or deceleratingindependently from the driving speed.

That is, if the exerciser 1000 intends to accelerate from a currentspeed, the current value X_(r) ^(T) gets smaller than the past valueX_(r−1) ^(T), whereas if the exerciser 1000 intends to decelerate from acurrent speed, the current value X_(r) ^(T) gets greater than the pastvalue X_(r−1) ^(T).

The exerciser position change rate determining step S4161 is a step fordetermining a degree which the exerciser 1000 intends to accelerate ordecelerate from the current speed, and it is understood that if a changerate per unit time is large, then the exerciser intends to accelerate ordecelerate quickly.

If the position change rate per unit time of the exerciser 1000 islarge, the control sensitivity is increased by adjusting, i.e.,increasing the control constant, and if the position change rate perunit time of the exerciser 1000 is small, then the control sensitivityis decreased by adjusting, i.e., decreasing the control constant,whereby it is possible to rapidly follow an accelerating or deceleratingintention of the exerciser 1000.

The belt speed determining step S4162 is used to determine an actualdriving speed. A method for computing the driving speed is similar tothe method described in the reference position generating step S3000 ofFIG. 17.

If the driving speed is high, that is, if the belt speed is fast, thecontrol sensitivity is increased, and if the driving speed is slow, thatis, if the belt speed is low, the control sensitivity is decreased.

If the exerciser 1000 exercising at a high speed intends to decelerate,then the control sensitivity is increased since the exerciser 1000 mayface risk if a deceleration is slow.

To the contrary, if the exerciser 1000 exercising at a low speed intendsto decelerate, the control sensitivity is decreased since the exerciser1000 may feel uncomfortable or face risk if a deceleration is fast.

Referring to the target decelerations 210 and 220 of FIG. 1, it isunderstood that the target deceleration is low if the driving speed isslow, and the target deceleration is high if the driving speed is fast.

In the control sensitivity adjusting step S4170, the control sensitivityis adjusted as follow, based on the determination in the speed/changerate determining step S4160.

A control gain G1 is computed by adjusting the control sensitivity suchthat if it is determined in the exerciser position change ratedetermining step S4161 that a position change rate of the exerciser1000, i.e., a backward speed of the exerciser 1000, is large, then thecontrol constant is increased to increase the deceleration of the belt.If it is determined that it is small, then the control constant isdecreased (step S4162). A control gain G2 is computed by adjusting thecontrol sensitivity such that if it is determined in the belt speeddetermining step S4162 that if the driving speed is fast, then thecontrol constant is increased, and if the driving speed is slow, thenthe control constant is decreased.

In the control gain adjusting step S4210, an operation on the two ormore control gains G1 and G2 which are obtained in an accelerating stateor a decelerating state or are obtained by adjusting the controlsensitivities by determinations according to various exemplaryembodiments of the present invention may be performed to therebygenerate a final control gain ΔV.

In the exemplary embodiment of the present invention, the control gainsare weight-averaged to generate the final control gain ΔV.

Another exemplary embodiment of the present invention to adjust thecontrol sensitivity is described below.

If the exerciser 1000 desires to reduce an acceleration or to deceleratein an accelerating state, the current value X_(r) ^(T) which representsa current position of the exerciser 1000 has a larger value than thepast value X_(r−1) ^(T), but it still has a smaller value than thereference position value X₀, and so the belt is accelerated contrary tothe decelerating intention of the exerciser 100.

The exemplary embodiment of the present invention to overcome theabove-described problem is described below in detail with reference toEquations.

Equation 1 can be expressed by a per unit time as follows:

$\begin{matrix}{{\Delta \; V_{r - 1}} = {{K_{p} \times \Delta \; X_{r - 1}} + {K_{i} \times {\sum\limits_{t = 0}^{r - 1}{\Delta \; X_{t}\Delta \; t}}}}} & \left\lbrack {{Equation}\mspace{14mu} 1a} \right\rbrack \\{{\Delta \; V_{r}} = {{K_{p} \times \Delta \; X_{r}} + {K_{i} \times {\sum\limits_{t = 0}^{r}{\Delta \; X_{t}\Delta \; t}}}}} & \left\lbrack {{Equation}\mspace{14mu} 1b} \right\rbrack\end{matrix}$

Equation 1a is a control equation which corresponds to an immediatelyprevious unit time (j=r−1) based on a current time (j=r), and Equation1b is a control equation which corresponds to the current time (j=r).

Equation 3 is obtained by allying Equations 1a and 1b.

ΔV _(r) =ΔV _(r−1) =K _(p)×(X _(r−1) ′=X _(r)′)+K _(i) ×ΔX _(r)×Δt  [Equation 3]

As can be seen by Equation 3, in case where the exerciser 1000 desiresto reduce an acceleration or to decelerate in an accelerating state, ina large-small relationship of variables on a right side of Equation 3,the past value X_(r−1) ^(T) is smaller than the current value X_(r)^(T), and the current value X_(r) ^(T) is smaller than the referenceposition value X₀.

In this instance, the exerciser 1000's intention is to reduce anacceleration or to decelerate. Therefore, since a current accelerationshould be smaller than a past acceleration, a value obtained bysubtracting the past speed change amount, i.e., a past accelerationΔV_(r−1) from the current speed change amount, i.e., a currentacceleration ΔV_(r) should be a negative value, and so a left side ofEquation 3 should be a negative number.

However, since a value obtained by subtracting the current value X_(r)^(T) from the reference position value X₀ is a positive number, and avalue obtained by subtracting the current value X_(r) ^(T) from the pastvalue X_(r−1) ^(T) is a negative number, if the proportional constantK_(p) and the integral constant K_(i) which are the control constantsmultiplied to them are fixed values, particularly, if a value of theintegral constant K_(i) is large, the right side becomes a positivenumber. This produces a problem in that an acceleration is increasedregardless of the exerciser's intention for reducing an acceleration ordecelerating.

For the foregoing reasons, in the exemplary embodiment of the presentinvention, the control constants are independently controlled.

When the exerciser 1000 moves back in an accelerating state, that is,when the current value X_(r) ^(T) corresponding to a position of theexerciser 1000 gets greater than the past value X_(r−1) ^(T), it ispossible to decrease the integral constant K_(i) which is a controlconstant of a portion for determining an absolute position of theexerciser 1000 or to increase the proportional constant K_(p) which is acontrol constant of a portion for determining a position change rate perunit time of the exerciser 1000 until a position of the exerciser 1000is ahead of the reference position with respect to the exerciserdetecting portion 3000, that is, the current value X_(r) ^(T) is smallerthan the reference position value X₀.

In the exemplary embodiment of the present invention, the integralconstant K_(i) is adjusted without adjusting the proportional constantK_(p), but it is possible to realize various modifications, for example,to increase the proportional constant K_(p) and to reduce the integralconstant K_(i).

Similarly, even when the exerciser 1000 desires to reduce a decelerationin a decelerating state or to accelerate, the same phenomenon occurs,and so it is preferred to independently adjust the control constants.

In case where the exerciser 1000 desires to reduce a deceleration in adecelerating state or to accelerate, in a large-small relationship ofvariables on the right side of Equation 3, the past value X_(r−1) ^(T)is greater than the current value X_(r) ^(T), and the current valueX_(r) ^(T) is greater than the reference position value X₀.

In this instance, since the exerciser 1000's intention is to reduce adeceleration or to accelerate, a current deceleration should be smallerthan a past deceleration. Therefore, a value obtained by subtracting thepast speed change amount, i.e., a past deceleration ΔV_(r−1) from thecurrent speed change amount, i.e., a current deceleration ΔV_(r) shouldbe a positive value, and so the left side of Equation 3 should be apositive number.

However, since a value obtained by subtracting the current value X_(r)^(T) from the reference position value X₀ is a negative number, and avalue obtained by subtracting the current value X_(r) ^(T) from the pastvalue X_(r−1) ^(T) is a positive value, if the proportional constantK_(p) and the integral constant K_(i) which are the control constantsmultiplied to them are fixed values, particularly, if a value of theintegral constant K_(i) is large, then the right side becomes a negativenumber. Thus, hat there occurs a problem in that a deceleration isincreased regardless of the exerciser's intention for reducing adeceleration or accelerating.

When the exerciser 1000 moves forward in a decelerating state, that is,when the current value X_(r) ^(T) corresponding to a position of theexerciser 1000 gets smaller than the past value X_(r−1) ^(T), it ispossible to decrease the integral constant K_(i) which is a controlconstant of a portion for determining an absolute position of theexerciser 1000 or to increase the proportional constant K_(p) which is acontrol constant of a portion for determining a position change rate perunit time of the exerciser 1000 until a position of the exerciser 1000is behind the reference position with respect to the exerciser detectingportion 3000, that is, the current value X_(r) ^(T) is greater than thereference position value X₀.

In the exemplary embodiment of the present invention, the integralconstant K_(i) is adjusted without adjusting the proportional constantK_(p), but it is possible to realize various modifications, for example,to increase the proportional constant K_(p) and to reduce the integralconstant K_(i).

FIG. 21 is a perspective view illustrating a control module for thetreadmill with the automatic speed control function according to theexemplary embodiment of the present invention. The control module ofFIG. 21 includes the control portion 7000 mounted on a base substrate400 containing a printed circuit board (PCB).

A control system for the treadmill with the automatic speed controlfunction may be realized such that an electrical braking portion 8000 iseclectically connected to the base substrate 400 containing the controlportion 7000.

The control module for the treadmill with the automatic speed controlfunction which has the base substrate 4000 further includes connectingterminals 410, 420, 430, 440, 450, and 460 which are electricallyconnected, respectively, with respective components of the treadmillaccording to the exemplary embodiment of the present invention.

The control module for the treadmill according to the exemplaryembodiment of the present invention uses a PCB as the base substrate4000, and the base substrate 4000 includes the control portion 7000which comprises semiconductor circuits and electrical wire lines 402which electrically connect the control portion 7000 and the connectingterminals 410, 420, 430, 440, 450, and 460.

The base substrate 400 further includes coupling holes 401 through whichthe base substrate 400 is coupled to a predetermined area of the bodyportion 2100 of the treadmill.

An exerciser detecting portion connecting terminal 410 serves totransmit, to the control portion 7000, a signal corresponding to aposition of the exerciser measured by the exerciser detecting portion3000 or the measured value.

An operating portion connecting terminal 420 serves to transmit a signalcorresponding to a manipulating button selected by the exerciser to thecontrol portion 7000 from the operating portion 2210 with themanipulating button.

A display connecting terminal 430 serves to transmit, to the displaydevice 2220, a signal corresponding to display information which isprocessed by the control portion 7000 to be provided to the exerciserand/or to transmit, to the control portion 7000, a signal correspondingto a manipulation of the exerciser on a touch screen or a touch padarranged in the display device 2220.

A power supply portion connecting terminal 440 serves to transmitelectrical power supplied from the power supply portion 2500 to thecontrol portion 7000 to drive the semiconductor circuits in the controlportion 7000.

An electrical braking portion connecting terminal 450 serves to transmitthe second control signal to the electrical braking portion 8000 whenthe switching portion 8100 in the electrical braking portion 8000 isdesired to be controlled by the second control signal transmitted fromthe control portion 7000 as shown in FIGS. 3 to 9.

A motor driving portion connecting terminal 460 serves to transmit thefirst control signal to the motor driving portion 6000 from the controlportion 7000 in order to control a speed of the driving motor.

Even though not shown, the base substrate 400 may further comprise aconnecting terminal for transmitting a signal for detecting a drivingspeed containing a speed of the belt 5000 or a corresponding speedthereto.

In the exemplary embodiment of the present invention, a braking resistoris used as the electrical braking portion 8000, and a heat sink portionwhich is made of a metal such as aluminum to discharge a heat generatedin the braking resistor is also arranged.

The electrical braking portion 8000 further includes a driving portionconnecting line 8011 which is connected to the motor driving portion6000 to transfer regenerative energy flowing into the motor drivingportion 6000 to the electrical braking portion 8000 and/or a controlconnecting line 8012 for receiving the second control signal transmittedfrom the control portion 7000.

Electrical braking portion coupling holes 401 for coupling theelectrical braking portion 8000 to a predetermined area of the treadmillbody portion 2100 are also arranged.

Here, if the electrical braking portion 8000 serves as a regenerativeenergy processing portion in which the regenerative energy generated inthe driving motor 4000 when the electrical braking portion 8000 brakesthe driving motor 4000 is discharged or consumed, the electrical brakingportion 8000 can be called the regenerative energy processing portion,and the electrical braking portion connecting terminal and theelectrical braking portion coupling hole can be called a regenerativeenergy processing portion connecting terminal and a regenerative energyprocessing portion coupling hole, respectively.

In the exemplary embodiment of the present invention, the electricalbraking portion 800 may be arranged on the base substrate 400, and if acircuit for a regenerative braking is used as the electrical brakingportion 8000 instead of the braking resistor, an electronic circuit maybe arranged instead of the heat sink portion for discharging heat.

That is, the control module may be modified in configuration and form,depending on a configuration and form of the electrical braking portion8000.

A parallel port or a serial portion may be used as the connectingterminals described above, and a configuration and form of theconnecting terminals may be modified depending on various modificationsof the exemplary embodiment of the present invention.

1. A treadmill, comprising: a body having a belt for supporting anexerciser; an exerciser detecting portion installed in a predeterminedarea of the body to detect movement of the exerciser; a driving motorcoupled to the body to drive the belt; a control portion for generatinga first control signal for adjusting a rotation speed of the drivingmotor based on a signal received from the exerciser detecting portion; amotor driving portion for adjusting the rotation speed of the drivingmotor according to the first control signal received from the controlportion; and an electrical braking portion for reducing the rotationspeed of the driving motor.
 2. The treadmill of claim 1, wherein inorder to reduce the rotation speed of the driving motor, the motordriving portion generates a first braking torque, and the electricalbraking portion generates a second braking torque.
 3. The treadmill ofclaim 2, wherein the electrical braking portion generates the secondbraking torque when a provisional braking torque by the first controlsignal is equal to or greater than the first braking torque.
 4. Thetreadmill of claim 3, wherein the second braking torque is equal to orgreater than a difference between the provisional braking torque and thefirst braking torque.
 5. The treadmill of claim 3, wherein theelectrical braking torque comprises a switching portion which operatesto generate the second braking torque when the provisional brakingtorque is equal to or greater than the first braking torque.
 6. Thetreadmill of claim 1, wherein the electrical braking torque comprises aswitching portion which operates when a voltage of regenerative energyflowing into the motor driving portion from the driving motor is equalto or more than a predetermined reference in case of decreasing therotation speed of the driving motor.
 7. The treadmill of claim 6,wherein the switching portion operates by a second control signaltransmitted from the control portion.
 8. The treadmill of claim 1,wherein the electrical braking portion comprises a switching portionwhich operates when a voltage applied between both output terminals of aconverting portion of the motor driving portion is equal to or more thana predetermined reference.
 9. The treadmill of claim 1, wherein theelectrical braking torque comprises a braking resistor which convertsregenerative energy flowing into the motor driving portion from thedriving motor into heat in case of decreasing the rotation speed of thedriving motor.
 10. The treadmill of claim 9, wherein both ends of thebraking resistor are electrically connected to both output terminals ofthe converting portion of the motor driving portion, respectively. 11.The treadmill of claim 10, wherein one end of the braking resistor iselectrically connected to one end of a switching portion which operateswhen a voltage of the regenerative energy is equal to or more than apredetermined reference.
 12. The treadmill of claim 1, wherein theelectrical braking torque transfers at least a part of regenerativeenergy flowing into the motor driving portion from the driving motor toa power supplying portion for supplying electrical power to the motordriving portion in case of decreasing the rotation speed of the drivingmotor.
 13. The treadmill of claim 12, wherein the electrical brakingportion comprises a switching portion which operates when a voltage ofthe regenerative energy is equal to or more than a predeterminedreference. 14.-28. (canceled)
 29. A control module for a treadmill,comprising: a base substrate with an electrical wire line formedtherein; a control portion coupled to the base substrate and having asemiconductor circuit electrically connected to the electrical wireline; and a connecting terminal coupled to the base substrate andelectrically connected to a motor driving portion for driving a drivingmotor and an exerciser detecting portion for measuring a position of anexerciser, wherein the control portion adjusts a rotation speed of thedriving motor based on a signal transmitted from the exerciser detectingportion and transmits a first control signal to the motor drivingportion to provide an electrical braking torque to the driving motor inorder to decelerate the driving motor. 30.-37. (canceled)
 38. Thecontrol module for the treadmill of claim 29, further comprising, anelectrical braking portion which is electrically connected to the motordriving portion and provides the electrical braking torque.
 39. Thecontrol module for the treadmill of claim 38, wherein the electricalbraking torque comprises a resistor, and the control module furtherincludes a heat sink portion which is made of a metal to discharge heatgenerated in the resistor.
 40. The control module for the treadmill ofclaim 38, wherein in order to decrease the rotation speed of the drivingmotor, the motor driving portion generates a first braking torque, andthe electrical braking portion generates a second braking torque. 41.The control module for the treadmill of claim 40, wherein the electricalbraking portion generates the second braking torque when the electricalbraking torque is equal to or greater than the first braking torque. 42.The control module for the treadmill of claim 41, wherein the secondbraking torque is equal to or greater than a difference between theelectrical braking torque and the first braking torque.
 43. The controlmodule for the treadmill of claim 41, wherein the electrical brakingtorque comprises a switching portion which operates when the electricalbraking torque is equal to or greater than the first braking torque. 44.(canceled)